1000 km, 10 hours for highways, 20 hours for national highways, which is more fuel-efficient? If it is all smooth, the national highway is more fuel-efficient than the high-speed, and those who say that the high-speed is more fuel-efficient, you can take it. From the perspective of economic cost, the national highway is certainly lower, the problem of the national highway is not the cost of oil, but the time consumption, and the national road condition is complicated, a fine, the saved oil money and tolls will be put in.
Please note that I am talking about the situation that the national highway and the highway are smooth, you say that the national highway traffic jam costs oil, which road traffic jam costs oil, and it has nothing to do with whether you run the national highway or the highway. It is also said that there are many traffic lights on national highways, in addition to traffic lights when passing through villages and towns, the number of traffic lights on national highways is much less than that of urban roads, and it does not affect the conclusion that national highways are more fuel-efficient than high-speed roads. Why is the national highway more fuel-efficient?
As we all know, cars have the most economical speed, the most economical speed of general family cars is 50-80km/h, that is, the "dessert area" of fuel consumption. Below or above this speed, fuel consumption will increase. The economic speed is mainly because of the efficient efficiency range of the engine and the transmission ratio of the gearbox, for example, taking the fuel consumption chart of the following 3.3L V6 engine as an example, the horizontal shaft represents the engine speed, the longitudinal shaft represents the torque output of the engine, and the curve in the middle of the coordinates represents the iso fuel consumption curve, indicating the fuel consumption of the engine at different torques and speeds.
From this coordinate, it can be seen that at a speed of 2000 rpm and a torque of 200 Nm, the engine is the most fuel-efficient. And this is a large displacement self-priming engine, the general small displacement turbocharged engine, its optimal efficiency range of the speed is less than 2000 rpm, about 1500 rpm or so.
The gearbox's gear ratio is usually the higher the gear, the smaller the gear ratio, so we can use a method to simply and rudely estimate the most economical speed of our own model, that is, the gear is in the highest gear, and the lowest speed your car can maintain.
Why is it said that there is no national highway to save fuel on high speeds? That's because at high speed, the wind resistance is too large, and studies have shown that when the speed exceeds 100, the biggest resistance comes from the wind resistance, and more than 60% of the fuel consumed is used to overcome the wind resistance, which is more obvious for SUV models. Therefore, in the case of long-distance driving and the roads are smooth, the fuel consumption of high-speed highways is 1-2 times higher than that of national highways.
It is also believed that high-speed driving speed is fast, and the engine has a short time to turn far, so the fuel consumption is low. But fuel consumption has nothing to do with how much time you run, because fuel consumption is not calculated based on time, but in 100 kilometers. No matter how long you run, as long as you are in the high efficiency range as much as possible, your fuel consumption is relatively low.
Therefore, under normal circumstances, the national highway must be more economical, taking the 1000km distance as an example, China's high-speed charging standard is about 0.5 yuan per kilometer, that is to say, 1000 km mileage, running high-speed toll expenses are about 500 yuan. National highways generally do not charge tolls, so in terms of tolls, running high-speed will be 500 yuan higher than the cost of national highways. In terms of fuel consumption, the fuel consumption of high-speed is 1-2 liters higher than that of national highways, we calculate according to 1 liter, calculated according to the oil price of 6 yuan per liter, running high-speed costs 60 yuan more than national highways.
However, the national road conditions are complex, there are more forks, drivers need to be highly vigilant, coupled with more national highway probes, a violation can make you more than worth the loss. And 1000km away, counting the rest time, take the national highway at least 20 hours, unless you are a self-driving tour to see the scenery all the way, otherwise there is no need to spend so long to take the national highway.
All in all, choose high-speed or national highway, one depends on the purpose of your travel, and also depends on the mileage, generally more than 200km, it is not recommended that you take the national highway, long-term driving will make people very tired, more than worth the loss.