What are the differences between a spark plug gasoline engine and a glow type gasoline engine?
EPHIL's RC gasoline model engine includes X series and XG series. The X series represents gasoline engines that use spark plugs and CDI. The XG series represents a glow type engine that applies the glow plug as the ignition method. The commonality between the two series of engines is that they both use gasoline as the main fuel and require an additional battery to power the spark plug or glow plug. Additionally, they show the similarity in terms of power performance (output power/rpm).
In general, spark plug engines and glow type engines are two different types of internal combustion engines, with several key differences in their working principles and applications.
1. Ignition Method:
- Spark Plug Engine: Spark plug engines ignite the fuel and gasoline mixture in the cylinder by generating a spark, initiating the combustion process.
- Glow Plug Engine: Glow plug engines ignite the fuel through a heated element without requiring an external ignition source (High frequency spark). This heated element can be a heated component or achieve high temperatures through compressed air.
2. Combustion Efficiency:
- Spark Plug Engine: Combustion in spark plug engines is influenced by the ignition system. While fuel combustion is relatively concentrated, issues such as poor ignition or ignition delay may occur under certain conditions.
- Glow Plug Engine: Combustion in glow plug engines is initiated by a heated element, allowing for more reliable control of ignition timing and thus more stable fuel combustion.
3. Accelerated linearity:
- Due to the characteristic of spark ignition, in many cases, rapid throttle up a spark plug engine may experience sudden acceleration changes. Requiring high proficiency in aircraft control.
- The acceleration performance of the glow type engine is basically linear, and the acceleration change is relatively smooth when throttle up the engine. Relatively easier to control.
4. Weight of ignition module:
- CDI ignition module for the X-series spark plug engine: 104 g (single cylinder type); 175 g (twin cylinder type)
- AET power system for the XG-series glow type engine: 30 g (single cylinder type); 35 g (twin cylinder type)
- Weight of CM6 spark plug: 13.5 g
- Weight of E8 glow plug: 4 g
5. Carburetor adjustment and ignition timing:
Due to the different requirements for the fuel-gas mixture ratio upon the two engines, in order to get the good performance, the carburetor needs to be adjusted the low-speed needle/high-speed needle to different positions. But don't worry about this, the EPHIL engine was already equipped the adjusted carburetor when it was assembling.
- Spark plug engines require adjusting the ignition timing/angle to match the optimal output power. This can be achieved by adjusting the angle/position of the Hall sensor.
- Glow type engines do not require adjustment of ignition timing/angle.
6. Electromagnetic interference (EMI):
- Most RC aircraft on the market that use CDI as ignition devices are inevitably affected by EMI in their control systems or receivers, which is a physical phenomenon caused by high-frequency voltage pulses.
- AET power system outputs a continuous low voltage, therefore it does not cause EMI.
7. Power consumption of battery:
- Due to the continuous ignition required by CDI, a stable current needs to be provided by the battery, a larger capacity battery is needed.
- AET power system does not ignite the glow plug when the engine is running at high speed, also does not consume any electrical energy. The high temperature generated by the rapid compression of air and ignition process can continuously keep the engine running. Therefore, it does not require a larger battery capacity.
8. Applications:
- Spark Plug Engine: Spark plug engines provide higher power output during startup and acceleration. eg: the mall scale RC model airplane.
- Glow Type Engine: Glow type engines typically offer better durability and reliability under prolonged operation and high loads. eg: the larger scale RC model airplane or UAVs.
9. Maintenance and Care:
- Spark Plug Engine: Spark plugs require regular replacement, and maintenance of the ignition system is necessary for proper operation.
- Glow Plug Engine: Glow plug engines require relatively less maintenance since there are no ignition system components that need frequent replacement or upkeep.
In summary, both spark plug engines and glow type engines have their own advantages and characteristics, and it is necessary to choose the most suitable engine based on the different fields of use.
