The automobile world is changing before our eyes, hybrid power plants are increasingly replacing conventional powertrains, and the good old gasoline “aspirators” give way to supercharged engines of relatively modest volume. In Europe, engines that consume diesel fuel have long been confidently crowding the “eaters” of gasoline, and in our country they are more confidently pushing their way. And how do all these various units manifest themselves in the cold, that is, provide heat to our loved ones?
For the experiment, we took five golf class hatchbacks. So, at our disposal: Opel Astra with a 1.4-liter gasoline turbo engine with 140 hp, Volkswagen Golf with a 2-liter turbodiesel with 110 hp, Mazda3 with a 1.6-liter naturally aspirated gas engine with 105 liters.s., a hybrid Toyota Prius, the power plant of which includes a 1.8 liter petrol aspirated and 99 hp, as well as a Renault Megane with a 2 liter naturally aspirated petrol unit and 138 hp.
Of course, we must make a reservation that in fact we have the opportunity to compare not the engines themselves, but a complex of a motor, a cooling system and a heating and ventilation system. The total efficiency of this complex depends on a large number of parameters - such as the heat transfer efficiency in the contours of the engine cooling jacket and heater radiator, thermostat settings, the total heat capacity of the cooling system, the performance of the air conditioning fan, etc. However, the main contribution to the heating capabilities of the entire complex is still made by the engine.
To room temperature
The comparison methodology we have chosen is elementary. In cars that have stood all night in cold weather, the engine starts, the temperature and fan speed in the climate system are set to maximum, and the entire air flow is directed to the legs. After that, we measure the air temperature in the area of the legs and see how long it will rise to the completely “inhabited” + 20ºС. If this does not happen within half an hour, stop the stopwatch and fix the result of the air temperature. Such a strategy, which was absolutely unprofitable from the point of view of the earliest possible warming up of the cabin, was chosen by us intentionally - so that the difference between the machines appears as vividly as possible.
Heat goes through wires
By the way, the ability of our wards today to establish a “warm, friendly atmosphere” in the cabin is not limited only to the operation of the “stove”. All cars are equipped with electric seat heating, and we also subjected it to a close study using a thermal imaging camera.
The smallest motor in our test today took 27 minutes 30 seconds to bring the temperature of the air supplied to the interior to the desired room temperature of 20 ° C. The efficiency of electric seat heating in Astra is low. The thermogram clearly shows that the heating elements are located under the upholstery of the seats very sparse. But Opel was the only one in the five equipped with steering wheel heating!
The expected outsider of our thermal test is a diesel with a result of 6ºC half an hour after launch. And the reason for this is its high energy efficiency, however paradoxical it may sound. The energy of the burned fuel is converted into mechanical energy by the diesel engine so efficiently that there is almost no excess heat. Buyers of diesel cars can be advised to equip them with additional heaters (electric or fuel), which are often present in the list of options. But in terms of electric seat heating, the Golf is the best - it fries quickly, and the heating elements are placed evenly over the area of the pillows and backs.
The popular “nesting doll” in our country almost repeated the performance of the Opel Astra: it took 28 minutes 26 seconds to heat the air in the driver’s legs to a temperature of 20 ° C. In principle, the result of a 1.6-liter atmospheric unit can be used as a kind of "reference point", because it is precisely such motors that are most common in our class, and many are well aware of their heating talents. The seat heating in the Mazda3 left a good impression: it has a high density of heating elements, stepless adjustment of the intensity of work and a rather high speed of "roasting of loin parts".
The “cool” attitude of hybrids to the inhabitants of the cabin was confirmed in practice: in 30 minutes the air temperature in the lower part of the cabin grew only to 14ºС. The algorithm of the hybrid installation is to blame. Throughout the half an hour, the gasoline engine was periodically turned off (as the battery was charging) and started again, as soon as the energy supply in the battery became lower than a certain level. By the way, in traffic jams, the engine also turns off as soon as possible. The electric heating elements in the Toyota Prius quickly warm the seats, but they are located unevenly and not in the most optimal way.
Our “Frenchman” turned out to be thermophilic in the most positive sense - he managed to raise the temperature to the required 20 ° C faster than anyone. The most voluminous 2-liter engine took 16 minutes 43 seconds. In fact, it was precisely this alignment that we predicted when we started the competition for the speed of heating the salons. As for the "electric heating" of the seats, its speed and efficiency turned out to be average due to the not too "dense" arrangement of thermocouples. In addition, the seat heating is single-stage, and it is impossible to regulate its intensity, as on other machines.
A thermal imager is a device that detects infrared radiation. In other words, he “sees” heat and distinguishes between objects with different temperatures. Perceived by the thermal imaging matrix, but not visible to the human eye, the infrared radiation is converted by the device into a video signal, which clearly shows the temperature difference on the display. Thermography (research with the help of thermal imagers) finds application in various fields - for example, such as medicine, construction, energy, industry (including automotive), restoration of art objects, hunting, fire fighting and others. The Flir T640 thermal imager used by us is the top-end device of the professional series. It has a high resolution thermal imaging matrix and a maximum range of functions, has a touch screen and wireless connectivity for transmitting information.
Alexander Stolyarov, editor:
- The distribution of places in our “heating” rating turned out to be logical and quite predictable. In the last place is a car with a diesel engine, which has the highest efficiency. You have to pay for efficiency: modern diesel engines can be warmed up to operating temperature in winter only on the go. The difficulties with the winter operation of hybrid cars are also well known, and the fourth Prius is quite natural. The difference between the bronze and silver medalists was minimal, and their result indicates the high efficiency of modern gasoline engines. Well, the winner was the car with the most “voluminous" and archaic design unit.