A widely used cold weather starting aid for engines of small craft is the ether capsule. The ether capsule serves to inject a highly volatile fluid (ether) into the air intake system to assist ignition of the fuel.

An ether capsule primer (fig. 10-12) consists of a discharge cell, discharge nozzle, and pressure primer capsule, which contains a liquid ether mixture. The discharge cell and the discharge nozzle are connected together by a suitable length of tubing. The discharge cell is a metal enclosure containing a piercing pin and a removable cap for insertion of the pressure primer capsule. When the lever is operated, it forces the capsule against the piercing pin.

The discharge cell is installed at the control station in a vertical position so that the neck of the capsule is always down toward the piercing pin. The discharge nozzle is installed through a pipe connection at the forward end of the intake manifold.

When you are using the ether capsule primer, press the engine starter switch. As soon as the starting motor brings the engine up to cranking speed, operate the discharger lever to discharge the capsule. Continue cranking while the ether mixture is being forced rapidly through the connecting tube to the intake manifold where it is sucked into the cylinders. The capsule requires approximately 15 seconds to discharge, and the diesel engine should start during this interval.

WARNING

Ether must not be used in connection with the grid resistor or glow plug methods. With the high volatility of ether, additional heat could cause ignition in the intake manifold or preignition in the combustion chamber.

HEATERS

Two other types of starting aids are the cylinder-block jacket-water heater and the engine-oil heater. When fuel enters a cold combustion chamber and the intake air is also cold, the fuel fails to evaporate. Instead, it collects in the cylinders, washes the lub-rication from the cylinder walls, and dilutes the crankcase oil. These problems are corrected when the coolant or lubricating oil is heated. These heaters function to keep the engine components warm at all times. Moreover, they minimize engine component wear during starting and warmup. The heaters may use steam or electricity as a heat source for the coolant or lubricating oil.

NOTE: Starting aids are not intended to correct deficiencies, such as a weak battery or a poorly tuned engine. They are intended for use when other conditions are normal but the air temperature is too low for the heat of compression to ignite the fuel-air mixture in the cylinders. For additional information on starting aids refer to Naval Ships Technical Manual, chapter 233.

SUMMARY

As an Engineman third class, you must know the purpose and principles of operation of the four types of starting systems used in Navy diesel engines: (1) electric, (2) hydraulic, (3) air motor, and (4) compressed air admission.

You should be aware of the various devices that aid the starting of an engine in cold temperatures. Starting an engine in cold weather may require the use of starting aids that may either (1) heat the air in the cylinder, (2) heat the intake air, (3) inject a highly volatile fluid into the air intake, or (4) heat the lubricating oil and/or the coolant. A commonly used starting aid is the ether capsule. The basic reason for its use is that it will not take away battery power that is needed for cranking.

If you are uncertain about the engine starting systems discussed in this chapter, you should reread the sections that are giving you trouble before continuing to chapter 11.

Figure 10-12.-Ether capsule primer.