FUEL ECONOMY

Hawke's Bay Tribune, Volume XX, Issue 239, 27 September 1930, Page 13

FUEL ECONOMY

POINTS WORTH KNOWING. HOW TO INCREASE MILEAGE. It is one thing (says Diesel, in the “Pastoral Review 1 ’) to pilot a car from one place to another with just the object in mind of reaching one’s destination in the shortest possible time, but quite another to cover the same distance with the fixed purpose of arriving at the journey’s end safely, and possessed of the certain knowledge that you have done everything in your power to save all unnecessary wear and tear while on the trip, and to assure that the greatest economy in fuel and oil has been the order of the day.

A car operating economically is a car operating efficiently, and although my readers may not realise the fact, it is possible for two drivers to handle the same car, over the same course, under exactly similar conditions, and for one to use nearly double the quantity of motor spirit that has been used by the other. lam reminded of an actual case which concerned a car 1 had sold to a friend. He had used the car in his business, and once a week travelled from his home at Brighton. Victoria, to a seaside town 68 miles distant. When driving himself, he always used six gallons of motor spirit for the total journey of 13G miles. He was not fond of driving, and when at times I accompanied him he was always glad to pass the wheel over to me. We noticed, not once, but on numerous occasions, that my total gallonage for the trip was four and a-half, working out at slightly more than 30 miles per gallon, whereas his average was something in advance of 22 miles per gallon. After making him drive several times when I was in the car. I came to the conclusion that, firstly, he travelled very much faster than I did, and, secondly, he maintained n wider throttle position at all times. His faster driving occasioned more easing up and getting under way again due to blocks in the traffic, and when on a hill he would always depress his accelerator pedal to the limit of its travel from the very bottom to the top. THROTTLE CONTROL. I have no doubt that many of my readers will appreciate the fact that there is, in every car, a position relative to this accelerator pedal which seems to give the host result, although not wide open. When such position is attained there is a resultant sucking noise in the inlet manifold which will decrease in volume if the throttle is moved ever so slightly in cither the open or shut direction. It is a position where the engine seems to be doing its work ‘ easily without am' sffort of effort, yet it never seems to be a wide open position.

If such a throttle setting is maintained as nearly as possible over an extended run it will be found that the great: ' fuel economy will result. It is, in fact referred to ns the “economy position” by a number of leading automobile engineers, whose works I have enpoyed reading. They sa> that, particularly on a hill, when engine revolutions may bo progressively falling off in number, nothing is to be .gained by opening the throttle beyond this position. To do so would tend more or less towards choking the motor.

ENGINE TEMPERATURE. Going further into the subject of economy, “engine temperature” is an item which has a direct bearing on this. A cold engine is a wasteful engine as likewise is an excessively hot one. Many cars to-day have what is known as a thermostatic control of the cooling system, and the owners of such need only ascertain from time to time that the thermostat is functioning properly. In such a case one can rest assured that the engine temperature will maintain itself at a level consistent with efficiency, but if your car has a manual heat control of the typo where shuttors placed in front of the radiator can be opened or closed by hand, care should bo taken to operate this control to keep the engine temperature within the “driving range,” which is usually clearly marked on the thermometer. Never start away on a trip with the water level low in the radiator. This will upset your calculations always with regard to heat control, and in many cars the thermometer will give a fictitious reading if the level is not right up. Actual engine temperature may bo much higher than the thermometer signifies, particularly if the water level is exceptionally low. This I repent, is the case with some types of indicators, but not all. An engine which is exceptionally hot will always get away with a large quantity of lubricating oil, and a very cold engine will be extravagant in the fuel direction. If in the latter case black fumes ore noticed coming from the exhaust pipe, there is obnormal waste taking place—the fumes need not be jet black to denote this, but imply dark in colour. A good economical exhaust may have noticed this condition after using the choke or stranger when first starting up on a cold morning. Always remember that it is difficult to cool an engine which has become excessively hot. It will not regain

normal working temperature usually, unless a halt is called and it is allowed to cool right off before restarting. It is not an economical practice to push a car over a big hill in “top gear” whore it is labouring for a long time, but far better to drop to a lower gear and run with a “light throttle.” The 'gear box is placed in the chassis for this purpose, and it should be used on every occasion when there is the least suggestion of engine labouring.