Diesel engines are complex machines. These machines work through a combination of pneumatic, mechanical, and electrical systems. Although diesel engines get their power from fuel, they still have electrical systems that power the electronics and accessories of the vehicle. The battery, which is part of the electrical system, is also responsible for starting the engine.
Differences Between Natural Gas and Diesel Fuel Powered Electrical Systems
Gasoline vehicles and diesel-powered vehicles have similar electrical systems in their alternators, solenoids, and starters.
Where they differ is the capacity of the batteries. In a diesel engine, when the battery enables the starter, a diesel battery needs to also have enough power for the glow plugs to warm the combustion chambers. Then, it must allow enough heat and compression to build up in the cylinders for the fuel to ignite.
When temperatures are lower, even more electricity is required to create enough heat to warm the different components so the engine can start. Some cold-weather starting products can be added to diesel engines to help heat the starting system. Some provide localized and controlled heat, such as an oil pan heater, a fuel warmer, and a battery warmer. A block heater can be used to heat up engines or truck cabins. With any of these cold-weather starting products, a thermostat is helpful to monitor the temperature of the engine to ensure all components keep the engine in a safe temperature range.
The Starting System
An alternator, starting motor, and battery comprise the starting system of a diesel engine. This starting system, as the name suggests, gets the engine started. A diesel engine needs to rotate somewhere between 150 and 250 rotations per minute to generate enough torque to start. The torque is used to initiate the flywheel rotation and turn the crankshaft, which moves the pistons. The larger the engine, the more torque is needed to achieve the cranking speed necessary.
The alternator charges the battery in the system. It converts some of the mechanical energy from the engine to electrical energy to charge the battery. The battery is then used to power the cranking motor during startup.
Small electrical motors called starters use electrical energy to create mechanical motion when you start the vehicle.
Electrical energy stored in the battery is used by the starter relay to energize the starter solenoid to turn the engine over. A solenoid is a small device that is made of a wire coil, housing, and a plunger. The purpose of a solenoid is to convert electrical energy into mechanical work. When an electrical current is exposed to a solenoid, it forms a magnetic field around the coil. This magnetic field draws in the plunger, which creates mechanical force.
The drive pinion is moved during the starting process by the solenoid. The solenoid is in the diesel engine's starting motor.
Preventing Potential Problems
You can take some proactive measures to prevent problems in your diesel engine's electrical system before they arise.
- Turn the lights off. When you aren't using the lights in your vehicle, make sure they are turned off. Leaving them on while they are not being used will cause excessive wear and can drain the battery.
- Regularly inspect the system. You can catch a problem early by making a habit of checking on the plugs, wires, and battery cables on a routine basis. Check for worn parts, corrosion, debris, or broken parts.
- Clean the system. While you are inspecting the system is a great time to clean anything that may have excessive debris. Keep it clean and clear for best results.
Potential Problems
Even with regular maintenance, you will still encounter parts that fail or eventually wear down. Here are some common problems with the electrical system and what is causing the problems.
- The alternator won't charge - When an alternator does not charge, it is usually due to dirt, debris, corrosion, and worn parts.
- The battery will not hold a charge - Dirty connections, corroded cables, worn belts, or damaged pulleys may be the cause of a battery charge not holding.
- Poor starter operation performance - Poor starter operation could be indicative of a handful of different problems:
- A broken ignition switch
- A burned-out solenoid
- Loose connections
- Developing corrosion
- A discharged (but not dead) battery
- A complete failure of the battery
Most of these problems can be avoided with regular inspections and maintenance.
If during your inspection you find yourself in need of anything for your engine, from a diesel pump plunger to a new camshaft, check our online inventory.
