1. How does a gas engine work?

2. What is the combustible or inflammable material used?

3. What is the supporter of combustion?

4. What are the gases exploded?

5. How is gasoline made into a gas?

6. What is the source of energy of the gas engine?

7. What are the two types of gas engines commonly used?

8. Explain the operation of each type.

9. How does the two-cycle engine differ from the four-cycle engine?

10. What is the object of compressing the charge in a gas engine?

11. Does the nitrogen of the air take part in the explosion?

12. What are the products of combustion in the explosion if we assume the gas is composed of hydrocarbons?

13. At what point should ignition take place to get best results?

14. Upon what does a successful and reliable ignition depend?

15. How is ignition accomplished in a gas engine?

16. Name two systems of ignition.

17. Give advantages and disadvantages of each system.

18. What is the great source of loss of power in a gas engine?

Problems

1. The horse-power of a four-cycle engine is estimated approximately by multiplying the area of the piston by the length of stroke, and this product by the number of revolutions per minute and dividing the final product by 15,000. What is the horse-power of a four-cycle gas engine with a 5 in. bore, 6 in. stroke, and 400 R. P. M.?

Fig. 183.   Carbureter in Section.

Fig. 183. - Carbureter in Section.

2. The proportion of gas and air in an explosive mixture is ordinarily a mixture of one volume of gas to seven to ten of air. How much air should be mixed with 6 cu. in. of gas?

3. The maximum pressure in a gas-engine cylinder may be calculated approximately by multiplying the gauge pressure of corn-pressure by four. What is the maximum pressure in a gas-engine cylinder if the gauge pressure is 70 lbs.?