Detroit Diesel DD15 Engine Service & Repair Manual

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Generated on 10-13-2008 General Information SCOPE AND USE OF THIS MANUAL This manual contains complete instructions on operation, adjustment (tune-up), preventive maintenance, and repair (including complete overhaul) for the DD15 Engine. This manual was written primarily for persons servicing and overhauling the engine. In addition, this manual contains all of the instructions essential to the operators and users. Basic maintenance and overhaul procedures are common to all DD15 Engines, and apply to all engine models. This manual is divided into numbered sections. Section one covers the engine (less major assemblies). The following sections cover a complete system such as the fuel system, lubrication system, or air system. Each section is divided into subsections which contain complete maintenance and operating instructions for a specific engine subassembly. Each section begins with a table of contents. Pages and illustrations are numbered consecutively within each section. Information can be located by using the table of contents at the front of the manual or the table of contents at the beginning of each section. Information on specific subassemblies or accessories within the major section is listed immediately following the section title. CLEARANCE OF NEW PARTS AND WEAR LIMITS New parts clearances apply only when all new parts are used at the point where the various specifications apply. This also applies to references within the text of the manual. The column entitled "Limits" must be qualified by the judgement of personnel responsible for installing new parts. For additional information, refer to the section entitled "Inspection" within this section. THE FOUR CYCLE PRINCIPLE FOR DIESEL ENGINES The diesel engine is an internal combustion engine, in which the energy of burning fuel is converted into energy to work the cylinder of the engine. In the diesel engine, air alone is compressed in the cylinder, raising its temperature significantly. After the air has been compressed, a charge of fuel is sprayed into the cylinder and ignition is accomplished by the heat of compression. The four piston strokes of the cycle occur in the following order: intake, compression, power and exhaust. Intake Stroke During the intake stroke, the piston travels downward, the intake valves are open, and the exhaust valves are closed. The down stroke of the piston facilitates air from the intake manifold to enter the cylinder through the open intake valve. The turbocharger, by increasing the air pressure in the engine intake manifold, assures a full charge of air is available for the cylinder. The intake charge consists of air only with no fuel mixture. Compression Stroke Page 1 of 24 Power Service Literature

At the end of the intake stroke, the intake valves close and the piston starts upward on the compression stroke. The exhaust valves remain closed. At the end of the compression stroke, the air in the combustion chamber has been compressed by the piston to occupy a space about one-seventeenth as great in volume as it occupied at the beginning of the stroke. Thus, the compression ratio is 18.1 Compressing the air into a small space causes the temperature of that air to rise. During the last part of the compression stroke and the early part of the power stroke, a small metered charge of fuel is injected into the combustion chamber. Almost immediately after the fuel charge is injected into the combustion chamber, the fuel is ignited by the hot air and starts to burn, beginning the power stroke. Power Stroke During the power stroke, the piston travels downward and all intake and exhaust valves are closed. As the fuel is added and burns, the gases get hotter, the pressure increases, pushing the piston downward and adding to crankshaft rotation. Exhaust Stroke During the exhaust stroke, the intake valves are closed; the exhaust valves are open, and the piston is on its up stroke. The burned gases are forced out of the combustion chamber through the open exhaust valve port by the upward travel of the piston. From the preceding description, it is apparent that the proper operation of the engine depends upon the two separate functions: first, compression for ignition, and second, that fuel be measured and injected into the compressed air in the cylinder in the proper quantity and at the proper time. GENERAL DESCRIPTION The DD15 Engine described in this manual is a four-stroke cycle, high speed, diesel engine. It uses an inline cast iron block and has a cast iron cylinder head that contains a duel overhead camshaft. The camshafts actuates all the valves (two intake, two exhaust per cylinder). The vertically aligned gear train, located at the rear end of the engine in a gear case, contains drive gears for the lubricating oil pump, crankshaft, camshafts, air compressor drive, fuel pump drive. Full pressure lubrication is supplied to all main, connecting, camshaft and rocker assembly bearings and to other moving parts. The oil spray nozzles spray engine oil continuously below the piston crowns to ensure that they are cooled. A gear-type pump draws oil from the oil pan through a screen and delivers it to the oil coolant module. The engine oil is first fed through the oil/water heat exchanger located on the oil coolant module. During the cold start phase of the Page 2 of 24 Power Service Literature

engine the oil/water heat exchanger will rapidly warm the oil. After the warm-up phase of the engine the oil/water heat exchanger will cool the engine oil. Once the engine oil has passed through the oil/water heat exchanger it then goes to the oil filter. In the oil filter part of the engine oil (about 90%) flows through the filter element and is cleaned. The rest of the oil (about 10%) goes into the oil centrifuge. The engine oil cleaned in the centrifuge and flows unpressurized back into the oil pan. Part of the oil goes to the camshaft frame where it feeds the camshaft bearings and rocker assemblies. The remainder of the oil goes to the main bearings and connecting rod bearings via the drilled oil passages in the crankshaft. The turbocharger is supplied with engine oil by an external oil line. Return flow of the engine oil by return ducts and return holes in the cylinder head and cylinder block and back to the oil pan. Coolant is circulated through the engine by a centrifugal-type water pump. The cooling system, including the radiator, is a closed system. Heat is removed from the coolant by the radiator. Control of the engine temperature is accomplished by thermostats that regulate the flow of the coolant within the cooling system. The fuel supply ensures that the fuel required for combustion is available under all operating conditions in the sufficient quantity, at the correct time and at the required pressure. Fuel to the individual cylinders is supplied via the Amplified Pressure Common Rail System (APCRS) which is supplied by the fuel low pressure circuit with fuel. The fuel low pressure circuit ensures that the fuel is cleaned and is provided in the sufficient quantities and at the required pressure to the APCRS Air is supplied by the turbocharger to the intake manifold and into the engine cylinders after passing through an air-to-air charge air cooler mounted ahead of the cooling system radiator. The charge air cooler cools the pressurized intake air charge coming from the turbocharger before it enters the intake manifold. Engine starting is provided by an electric motor energized by a storage battery. A battery charging alternator, with a suitable voltage regulator, serves to keep the battery charged. The DD15 Engine was designed to be electronically controlled. The Detroit Diesel Electronic Control (DDEC) system has evolved with the product. DDEC VI The DDEC VI Motor Control Unit (MCM) receives electronic inputs from sensors on the engine and vehicle, and uses the information to control engine operation. It computes fuel timing and fuel quantity based upon predetermined calibration tables in its memory. DDEC VI provides an indication of engine and vehicle malfunctions. The Motor Control Unit (MCM) continually monitors the DDEC VI system. Any faults that occur are stored as codes in the MCM's memory. A DDDL® can be used to read the codes. GENERAL SPECIFICATIONS The general specifications for the DD15 Engine are listed in Table "Specifications for the DD15 Engine" . Page 3 of 24 Power Service Literature

Filling Capacities are listed in Table "Filling Capacity" . Piston specifications are listed in Table "Piston Specifications" . Piston pin specifications are listed in Table "Piston Pin Specifications" . Fuel system specifications are listed in Table "Fuel System Specifications" . Crankshaft bearing specifications are listed in Table "Crankshaft Bearing Specifications" . Connecting rod specifications are listed in Table "Connecting Rod Specifications" . Connecting rod bearing specifications are listed in Table "Connecting Rod Bearing Specifications" . Cylinder block specifications are listed in Table "Cylinder Block Specifications" . See see Figure "Cylinder Designation and Firing Order" for the cylinder designation and firing order. Table 1. Specifications for the DD15 Engine Table 2. Filling Capacity Table 3. Piston Specifications General Specifications 14L Family Total Displacement (L) 14.8 Number of Cylinders 6 Valve Control DOHC Number of Valves per Cylinder (Intake/Exhaust) 2/2 Idle Speed 600 (rpm) Output 382 - 478 (kW) Combustion Pressure max. 250 (bar) Compression Ratio 18:0 Stroke 163 (mm) Hub Bore Ratio 1.17 Initial Filling Capacity of Oil Pan 44.5 l (47.02 qt) Oil Pan Capacity 40 l (42.27 qt) Oil Capacity of Oil Coolant Module 4.5 l (4.755 qt) Diameter 139 mm (5.472 in.) Total Height 124.5 mm (4.902 in.) Compression Height 83.5 mm (3.287 in.) Shank Length 54.5 mm (2.146 in.) Inside Diameter 23 mm (0.9055 in.) Outside Diameter 62 mm (2.441 in.) Page 4 of 24 Power Service Literature

Detroit Diesel DD15 Engine Service & Repair Manual

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