Toyota Prius Vehicle operation in various driving modes
Comparative data of Prius cars of various years of manufacture
Internal combustion engine Toyota Prius
Toyota Prius has an internal combustion engine (ICE) with a displacement of 1497 cc, which is unusually small for a car weighing 1300 kg. This is made possible due to the presence of electric motors and batteries that help the ICE when more power is needed. In a conventional car, the engine is designed for high acceleration and driving up a steep hill, so it almost always runs at low efficiency.The 30th body uses a different engine, 2ZR-FXE, 1.8 liter.Because the car can not be connected to the city network power supply (which is planned to be implemented by Japanese engineers in the near future), there is no other long-term source of energy and this engine must supply energy to charge the battery, as well as to move the car and power additional consumers such as air conditioning, electric heater, audio, etc. .e Toyota designation for engine Prius - 1NZ-FXE. The prototype of this engine is the 1NZ-FE engine, which was installed on Yaris, Bb, Fun Cargo", Platz cars. The design of many parts of the 1NZ-FE and 1NZ-FXE engines is the same. For example, cylinder blocks for Bb, Fun Cargo, Platz and Prius 11 However, the 1NZ-FXE engine uses a different carburetion scheme, and therefore the design differences are associated.The 1NZ-FXE engine uses the Atkinson cycle, while the 1NZ-FE engine uses the conventional Otto cycle.
In an Otto cycle engine, during the intake process, an air-fuel mixture enters the cylinder. However, the pressure in the intake manifold is lower than in the cylinder (because the flow is controlled by the throttle), and so the piston does the extra work of sucking in the air-fuel mixture, acting as a compressor. The intake valve closes near bottom dead center. The mixture in the cylinder is compressed and ignited at the moment the spark is applied. In contrast, the Atkinson cycle does not close the intake valve at bottom dead center, but leaves it open while the piston begins to rise. Part of the air-fuel mixture is forced into the intake manifold and used in another cylinder. Thus, pumping losses are reduced compared to the Otto cycle. Since the volume of the mixture that compresses and burns is reduced, the pressure during compression with this mixture formation scheme also decreases, which makes it possible to increase the compression ratio to 13, without the risk of detonation. Increasing the compression ratio increases the thermal efficiency. All these measures contribute to improving the fuel efficiency and environmental friendliness of the engine. The payoff is a reduction in engine power. So the 1NZ-FE engine has a power of 109 hp, and the 1NZ-FXE engine has 77 hp.
Engine/Generators Toyota Prius
Toyota Prius has two electric motors/generators. They are very similar in design, but differ in size. Both are three-phase permanent magnet synchronous motors. The name is more complex than the design itself. The rotor (the part that rotates) is a large, powerful magnet and does not have any electrical connections. The stator (the fixed part attached to the car body) contains three sets of windings. When current flows in a certain direction through one set of windings, the rotor (magnet) interacts with the magnetic field of the winding and is set in a certain position. By passing current in series through each set of windings, first in one direction and then in the other, the rotor can be moved from one position to the next, and so make it rotate. Of course, this is a simplified explanation, but it shows the essence of this type of engine. If an external force turns the rotor, the current flows through each set of windings in turn and can be used to charge a battery or power another motor. Thus, one device can be a motor or a generator depending on whether current is passed through the windings to attract the rotor magnets, or current is released when some external force turns the rotor. This is even more simplified, but will serve the depth of the explanation.
Motor/Generator 1 (MG1) is connected to the Power Distribution Device (PSD) sun gear. It is the smaller of the two and has a maximum output of around 18 kW. Usually, he starts the internal combustion engine and regulates the revolutions of the internal combustion engine by changing the amount of electricity produced. Motor/generator 2 (MG2) is connected to the ring gear of the planetary gear (power distribution device) and further through the gearbox to the wheels. Therefore, it directly drives the car. It is the larger of the two motor generators and has a maximum output of 33kW (50kW for the Prius NHW-20). The MG2 is sometimes referred to as a "traction motor" and its usual role is to propel the car as a motor or return braking energy as a generator. Both motors/generators are cooled with antifreeze.
Toyota Prius Inverter
Since motors/generators run on AC three-phase current, and the battery, like all batteries, produces direct current, some device is needed to convert one form of current to another. Each MG has an "inverter" that performs this function. The inverter learns the position of the rotor from a sensor on the MG shaft and controls the current in the motor windings to keep the motor running at the required speed and torque. The inverter changes the current in a winding when the magnetic pole of the rotor passes that winding and moves on to the next one. In addition, the inverter applies battery voltage to the windings and then switches it off again very quickly (at a high frequency) in order to change the average current value and hence the torque. By exploiting the "self-inductance" of the motor windings (a property of electrical coils that resist changing current), the inverter can actually push more current through the winding than is supplied by the battery. It only works when the voltage across the windings is less than the battery voltage, hence energy is saved. However, since the amount of current through the winding determines the torque, this current makes it possible to achieve very high torque at low speeds. Up to approximately 11 km/h, the MG2 is capable of generating 350 Nm (400 Nm for the Prius NHW-20) of torque at the gearbox. That is why the car can start moving with acceptable acceleration without the use of a gearbox, which usually increases the torque of the internal combustion engine. In the event of a short circuit or overheating, the inverter switches off the high voltage part of the machine. In the same unit with the inverter, there is also a converter, which is designed to reverse convert AC voltage to DC -13.8 volts. To deviate a little from theory, a bit of practice: the inverter, like motor-generators, is cooled by an independent cooling system. This cooling system is powered by an electric pump. If on body 10 this pump turns on when the temperature in the hybrid cooling circuit reaches about 48 ° C, then on bodies 11 and 20 a different algorithm for the operation of this pump is used: be “overboard” at least -40 degrees, the pump will still start its work already at turning on the ignition. Accordingly, the resource of these pumps is very, very limited. What happens when a pump jams or burns out: according to the laws of physics, antifreeze under heating from MG (especially MG2) rises up - into the inverter. And in the inverter, it must cool the power transistors, which heat up significantly under load. The result is their failure, i.e. the most common error on body 11: P3125 - inverter malfunction due to a burnt out pump. If in this case the power transistors withstand such a test, then the MG2 winding burns out. This is another common error on body 11: P3109. On the 20th body, Japanese engineers improved the pump: now the rotor (impeller) does not rotate in a horizontal plane, where the entire load goes to one support bearing, but in a vertical one, where the load is distributed evenly over 2 bearings. Unfortunately, this added little reliability. In April-May 2009 alone, 6 pumps on 20 bodies were replaced in our workshop. Practical advice for owners of 11 and 20 Prius: make it a rule at least once every 2-3 days to open the hood for 15-20 seconds with the ignition on or the car running. You will immediately see the movement of antifreeze in the expansion tank of the hybrid system. After that, you can drive safely. If there is no antifreeze movement there, you can’t drive a car!
Toyota Prius high voltage battery
high voltage battery(abbreviated VVB Toyota Prius) Prius in 10 body consists of 240 cells with a nominal voltage of 1.2 V, very similar to a D-size flashlight battery, combined in 6 pieces, into the so-called "bamboos" (there is a slight resemblance in appearance). "Bamboos" are installed in 20 pieces in 2 buildings. The total nominal voltage of the VVB is 288 V. The operating voltage fluctuates in idle mode from 320 to 340 V. When the voltage drops to 288 V in the VVB, starting the internal combustion engine becomes impossible. In this case, the battery symbol with the "288" icon inside will light up on the display screen. To start the internal combustion engine, the Japanese in the 10th body used a regular charger, which is accessed from the trunk. Frequently asked questions, how to use it? I answer: firstly, I repeat that it can only be used when the "288" icon is on the display. Otherwise, when you press the "START" button, you will simply hear a nasty squeak, and the red "error" light will light up. Secondly: you need to hook up a “donor” to the terminals of a small battery, i.e. either a charger or a well-charged powerful battery (but by no means a starting device!). After that, with the ignition OFF, press the "START" button for at least 3 seconds. When the green light turns on, the VVB will start charging. It will end automatically after 1-5 minutes. This charge is quite enough for 2-3 starts of the internal combustion engine, after which the VVB will be charged from the converter. If 2-3 starts did not lead to the start of the internal combustion engine (and at the same time "READY" ("Ready") on the display should not blink, but burn steadily), then it is necessary to stop useless starts and look for the cause of the malfunction. In the 11th body, the VVB consists of 228 elements of 1.2 V each, combined in 38 assemblies of 6 elements, with a total nominal voltage of 273.6 V.
The entire battery is installed behind the rear seat. At the same time, the elements are no longer orange "bamboos", but are flat modules in gray plastic cases. The maximum battery current is 80 A when discharging and 50 A when charging. The nominal capacity of the battery is 6.5 Ah, however, the car's electronics allow only 40% of this capacity to be used in order to prolong the life of the battery. The state of charge can only change between 35% and 90% of the full rated charge. Multiplying the battery voltage and its capacity, we get the nominal energy reserve - 6.4 MJ (megajoules), and the usable reserve - 2.56 MJ. This energy is enough to accelerate the car, driver and passenger to 108 km / h (without the help of the internal combustion engine) four times. To produce this amount of energy, an internal combustion engine would require approximately 230 milliliters of gasoline. (These figures are only given to give you an idea of the amount of stored energy in the battery.) The vehicle cannot be driven without fuel, even when starting at 90% full rated charge on a long descent. Most of the time you have about 1 MJ of usable battery power. A lot of VVB gets into repair precisely after the owner runs out of gas (in this case, the "Check Engine" icon and a triangle with an exclamation mark will light up on the scoreboard), but the owner tries to "reach out" to refueling. After the voltage drops on the elements below 3 V, they "die". On the 20th body, Japanese engineers went the other way to increase power: they reduced the number of elements to 168, i.e. left 28 modules. But for use in an inverter, the battery voltage is raised to 500 V using a special -booster device. An increase in the nominal voltage of MG2 in the NHW-20 body made it possible to increase its power to 50 kW without changing the dimensions.
The Prius also has an auxiliary battery. This is a 12-volt, 28 amp-hour lead-acid battery, which is located on the left side of the trunk (in the 20 body - on the right). Its purpose is to energize the electronics and accessories when the hybrid system is off and the main high voltage battery relay is off. When the hybrid system is running, the 12V source is a DC/DC converter from the high voltage system to 12V DC. It also recharges the auxiliary battery when needed. The main control units communicate via the internal CAN bus. The remaining systems communicate over the Body Electronics Area Network. The VVB also has its own control unit, which monitors the temperature of the elements, the voltage on them, the internal resistance, and also controls the fan built into the VVB. On the 10th body there are 8 temperature sensors, which are thermistors, on the "bamboos" themselves, and 1 is a common VVB air temperature control sensor. On the 11th body -4 +1, and on the 20th -3 +1.
Toyota Prius power distribution unit
The torque and energy of the internal combustion engine and motors/generators are combined and distributed by a planetary set of gears, called by Toyota "power split device" (PSD, Power Split Device). And although it is not difficult to manufacture, this device is quite difficult to understand and even more tricky to consider in full context all modes of operation of the drive. Therefore, we will devote several other topics to the discussion of the power distribution device. In short, this allows the Prius to operate in both series- and parallel-hybrid modes at the same time and get some of the benefits of each mode. The ICE can turn the wheels directly (mechanically) through the PSD. At the same time, a variable amount of energy can be taken from the internal combustion engine and converted into electricity. It can charge a battery or be passed on to one of the motors/generators to help turn the wheels. The flexibility of this mechanical/electrical power distribution allows the Prius to improve fuel efficiency and manage emissions while driving, which is not possible with a rigid mechanical connection between the combustion engine and the wheels, as in a parallel hybrid, but without the loss of electrical energy, as in a series hybrid. The Prius is often said to have a CVT (Continue Variable Transmission) - continuously variable or "constantly variable" transmission, this is the PSD power distribution unit. However, a conventional CVT works exactly the same as a normal transmission, except that the gear ratio can change continuously (smoothly) rather than in a small range of steps (first gear, second gear, etc.). A little later, we will look at how the PSD differs from a conventional continuously variable transmission, i.e. variator.
Usually the most asked question about the "box" of a Prius car: what kind of oil is poured there, how much in volume and how often to change it. Very often, there is such a misconception among car service workers: since there is no dipstick in the bark, it means that the oil does not need to be changed there at all. This misconception has led to the death of more than one box.
10 body: working fluid T-4 - 3.8 liters.
11 body: working fluid T-4 - 4.6 liters.
20 body: ATF WS working fluid - 3.8 liters. Replacement period: after 40 thousand km. According to Japanese terms, oil is changed every 80 thousand km, but for especially difficult operating conditions (and the Japanese attribute the operation of cars in Russia to these especially difficult conditions - and we are in solidarity with them), the oil is supposed to be changed 2 times more often.
I will tell you about the main differences in the maintenance of the boxes, i.e. about changing the oil. If in the 20th body, in order to change the oil, you just need to unscrew the drain plug and, having drained the old one, fill in new oil, then on the 10th and 11th bodies it is not so simple. The design of the oil pan on these machines is made in such a way that if you simply unscrew the drain plug, then only part of the oil will drain, and not the dirtiest. And 300-400 grams of the dirtiest oil with other debris (pieces of sealant, wear products) remains in the sump. Therefore, in order to change the oil, it is necessary to remove the box pan and, having poured out the dirt and cleaned it, put it in place. When removing the pallet, we get another additional bonus - we can diagnose the condition of the box by the wear products in the pallet. The worst thing for the owner is when he sees yellow (bronze) chips at the bottom of the pan. This box won't last long. The pan gasket is cork, and if the holes on it have not acquired an oval shape, it can be reused without any sealants! The main thing when installing the pallet is not to overtighten the bolts so as not to cut the gasket with the pallet. What else is interesting in the transmission: The use of a chain drive is quite unusual, but all ordinary cars have gear reductions between the engine and the axles. Their purpose is to allow the engine to spin faster than the wheels and also increase the engine generated torque to more torque at the wheels. The ratios with which rotational speed is reduced and torque increased are necessarily the same (neglect friction) due to the law of conservation of energy. The ratio is called the "total gear ratio". The total gear ratio of the Prius in the 11th body is 3.905. It turns out like this:
The 39-tooth sprocket on the PSD output shaft drives the 36-tooth sprocket on the first intermediate shaft through a silent chain (so-called Morse chain).
The 30-tooth gear on the first countershaft is connected to and drives the 44-tooth gear on the second countershaft.
The 26-tooth gear on the second countershaft is connected to and drives the 75-tooth gear at the differential input.
The value of the output of the differential to the two wheels is the same as the input of the differential (they are, in fact, identical, except when cornering occurs).
If we perform a simple arithmetic operation: (36/39) * (44/30) * (75/26), we get (to four significant digits) a total gear ratio of 3.905.
Why is a chain drive used? Because it avoids the axial force (force along the axis of the shaft) that would occur with conventional helical gears used in automotive transmissions. This could also be avoided with spur gears, but they produce noise. Thrust is not a problem on the intermediate shafts and can be balanced by tapered roller bearings. However, this is not so easy with the PSD output shaft. There is nothing very unusual about a Prius differential, axles and wheels. As in a conventional car, the differential allows the inner and outer wheels to spin at different speeds when the car turns. The axles transmit torque from the differential to the wheel hub and include an articulation to allow the wheels to move up and down following the suspension. The wheels are lightweight aluminum alloy and fitted with high pressure tires with low rolling resistance. The tires have a rolling radius of approximately 11.1 inches, which means the car moves 1.77 meters for each revolution of the wheel. Only the size of stock tires on 10 and 11 bodies is unusual: 165/65-15. This is a rather rare tire size in Russia. Many sellers, even in specialized stores, quite seriously convince that such rubber does not exist in nature. My recommendations: for Russian conditions, the most suitable size is 185/60-15. In the 20 Prius, the size of the rubber has been increased, which has a beneficial effect on its durability. Now more interesting: what is missing in the Prius, what is in any other car?
There is no stepped transmission, either manual or automatic - the Prius does not use stepped transmissions;
There is no clutch or transformer - the wheels are always hardwired to the ICE and motors/generators;
There is no starter - starting the internal combustion engine is done by MG1 through gears in the power distribution device;
There is no alternator - electricity is generated by motors/generators as needed.
Therefore, the structural complexity of the Prius hybrid drive is actually not much greater than that of a conventional car. In addition, new and unfamiliar parts such as motors/generators and PSDs have higher reliability and longer life than some of the parts that have been removed from the design.
Vehicle operation in various driving conditions
Toyota Prius engine start
To start the motor, MG1 (connected to the sun gear) rotates forward using the power from the high voltage battery. If the vehicle is stationary, the planetary ring gear will also remain stationary. The rotation of the sun gear therefore forces the planet carrier to rotate. It is connected to the internal combustion engine (ICE) and cranks it at 1/3.6 of the rotational speed of MG1. Unlike a conventional car, which supplies fuel and ignition to the internal combustion engine as soon as the starter begins to turn it, the Prius waits until MG1 has accelerated the internal combustion engine to approximately 1000 rpm. This happens in less than a second. The MG1 is significantly more powerful than a conventional starter motor. To rotate the internal combustion engine at this speed, it must itself rotate at a speed of 3600 rpm. Starting an ICE at 1000 rpm creates almost no stress on it because that is the speed at which an ICE would be happy to run on its own power. Also, the Prius starts by firing only a couple of cylinders. The result is a very smooth start, free of noise and twitch, which eliminates the wear and tear associated with conventional car engine starts. At the same time, I will immediately draw attention to a common mistake of repairmen and owners: they often call me and ask what prevents the internal combustion engine from continuing to work, why it starts for 40 seconds and stalls. In fact, while the READY frame is blinking, the ICE DOES NOT WORK! It turns him MG1! Although visually - a complete feeling of starting the internal combustion engine, i.e. The engine makes noise, smoke comes out of the exhaust pipe ..
Once the ICE has started to run on its own power, the computer controls the throttle opening to get the right idle speed during warm up. Electricity no longer powers MG1 and, in fact, if the battery is low, MG1 can generate electricity and charge the battery. The computer simply sets up MG1 as a generator instead of a motor, opens the engine throttle a little more (up to about 1200 rpm) and gets electricity.
Cold start Toyota Prius
When you start a Prius with a cold engine, its top priority is to warm up the engine and catalytic converter so that the emission control system can work. The engine will run for several minutes until this happens (how long depends on the actual temperature of the engine and catalytic converter). At this time, special measures are taken to control the exhaust during warm-up, including keeping the exhaust hydrocarbons in the absorber, which will be cleaned later and running the engine in a special mode.
Warm start Toyota Prius s
When you start a Prius with a warm engine, it will run for a short time and then stop. Idling will be within 1000 rpm.
Unfortunately, it is not possible to prevent the internal combustion engine from starting when you turn on the car, even if all you want to do is move to a nearby lift. This only applies to 10 and 11 bodies. On the 20th body, a different start algorithm is applied: press the brake and press the "START" button. If there is enough energy in the VVB, and you do not turn on the heater to heat the interior or glass, the internal combustion engine will not start. The inscription "READY" (Totob ") will just light up, i.e. the car is COMPLETELY ready to move. It is enough to switch the joystick (and the choice of modes on the body 20 is done with the joystick) to position D or R and release the brake, you will go!
The Prius is always in direct gear. This means that the engine alone cannot provide all the torque to drive the car vigorously. The torque for the initial acceleration is added by the MG2 motor driving directly the planetary ring gear connected to the gearbox input, the output of which is connected to the wheels. Electric motors develop the best torque at low rpm, so they are ideal for starting a car.
Let's imagine that the ICE is running and the car is stationary, which means that the motor MG1 rotates forward. The control electronics starts to take energy from the generator MG1 and transfers it to the motor MG2. Now, when you take energy from a generator, that energy has to come from somewhere. There is some force that slows down the rotation of the shaft and something that rotates the shaft must resist this force in order to maintain speed. Resisting this "generator load", the computer speeds up the internal combustion engine to add more power. So, the ICE is turning the planet carrier more hard, and MG1 is trying to slow down the rotation of the sun gear. The result is a force on the ring gear that causes it to rotate and start moving the car.
Recall that in a planetary gear, the torque of the internal combustion engine is divided 72% to 28% between the crown and the sun. Until we pressed the accelerator pedal, the ICE was just idling and producing no output torque. Now, however, the revs have been added and 28% of the torque is turning MG1 like a generator. The other 72% of the torque is transferred mechanically to the ring gear and therefore to the wheels. While most of the torque comes from the MG2 motor, the ICE does transfer torque to the wheels in this way.
Now we have to find out how the 28% of the ICE torque that is sent to the MG1 generator can possibly boost the start of the car - with the help of the MG2 motor. To do this, we must clearly distinguish between torque and energy. Torque is a rotating force, and just like a straight line force, no energy is required to maintain the force. Suppose you are pulling a bucket of water with a winch. She takes energy. If the winch is driven by an electric motor, you would have to supply it with electricity. But, when you have raised the bucket to the top, you can hook it with some kind of hook or rod or something else to keep it on top. The force (weight of the bucket) that is applied to the rope and the torque transmitted by the rope to the winch drum has not disappeared. But because the force does not move, there is no transfer of energy, and the situation is stable without energy. Likewise, when the vehicle is stationary, even though 72% of the ICE's torque is being sent to the wheels, there is no energy flow in that direction since the ring gear is not rotating. The sun gear, however, rotates quickly, and although it receives only 28% of the torque, this allows a lot of electricity to be generated. This line of reasoning shows that MG2's task is to apply torque to the input of a mechanical gearbox that does not require much power. A lot of current must pass through the motor windings, overcoming electrical resistance, and this energy is wasted as heat. But when the car is moving slowly, this energy comes from MG1. As the vehicle starts to move and picks up speed, MG1 rotates more slowly and produces less power. However, the computer may increase the speed of the internal combustion engine a little. Now more torque is coming from the ICE and since more torque must also go through the sun gear, MG1 can keep the power generation high. The reduced rotational speed is compensated by an increase in torque.
We've avoided mentioning the battery up to this point to make it clear how it's not necessary to get the car going. However, most starting is the result of the computer transferring power from the battery directly to the MG2 motor.
There are ICE speed limits when the car is moving slowly. They are due to the need to prevent damage to MG1, which will have to rotate very quickly. This limits the amount of power produced by the internal combustion engine. In addition, it would be unpleasant for the driver to hear that the ICE is revving up too much for a smooth start. The harder you press the accelerator, the more the ICE will rev up, but also the more power will come from the battery. If you put the pedal to the floor, approximately 40% of the energy comes from the battery and 60% from the internal combustion engine at a speed of about 40 km / h. As the car accelerates and the ICE revs up at the same time, it delivers most of the power, reaching about 75% at 96 km/h if you're still pushing the pedal to the floor. As we remember, the energy of the internal combustion engine includes what is taken by the generator MG1 and transferred in the form of electricity to the motor MG2. At 96 km/h, the MG2 actually delivers more torque, and therefore more power to the wheels, than is supplied through the planetary gear from the internal combustion engine. But most of the electricity it uses comes from MG1 and therefore indirectly from the ICE, not from the battery.
Accelerating and driving uphill Toyota Prius
When more power is needed, the ICE and MG2 work together to generate torque to drive the car in much the same way as described above for starting off. As the vehicle speed increases, the amount of torque the MG2 is able to deliver decreases as it begins to operate at its 33kW power limit. The faster it spins, the less torque it can put out at that power. Fortunately, this is consistent with the driver's expectations. When a conventional car accelerates, the gear box shifts up and torque on the axle is reduced so that the engine can reduce its speed to a safe value. Although it is done using completely different mechanisms, the Prius gives the same overall feel as accelerating in a conventional car. The main difference is the complete absence of "jerking" when shifting gears, because there is simply no gearbox.
So, the internal combustion engine rotates the carrier of the satellites of the planetary mechanism.
72% of its torque is sent mechanically through the ring gear to the wheels.
28% of its torque is sent to the MG1 generator via the sun gear, where it is converted into electricity. This electrical energy feeds the MG2 motor, which adds some extra torque to the ring gear. The more you press the accelerator, the more torque the internal combustion engine produces. It increases both the mechanical torque through the crown and the amount of electricity produced by the MG1 generator for the MG2 motor used to add even more torque. Depending on various factors such as the state of charge of the battery, the grade of the road, and especially how hard you pedal, the computer may direct additional battery power to MG2 to increase its contribution. This is how acceleration is achieved, sufficient to drive such a large car with an internal combustion engine with a power of only 78 hp on the highway. With
On the other hand, if the required power is not so high, iu part of the electricity produced by MG1 can be used to charge the battery even when accelerating! It is important to remember that the ICE both turns the wheels mechanically and turns the MG1 generator, causing it to produce electricity. What happens to this electricity and whether more battery electricity is added depends on a complex of reasons that we cannot all account for. This is handled by the vehicle's hybrid system controller.
Once you have reached a steady speed on a flat road, the power that should be supplied by the engine is used to overcome aerodynamic drag and rolling friction. This is much less than the power needed to drive uphill or accelerate a car. In order to operate efficiently at low power (and also not create a lot of noise), the internal combustion engine runs at low speeds. The following table shows how much power is needed to move the car at different speeds on a level road and the approximate rpm.
Note that the high vehicle speed and low ICE RPM put the power distribution device in an interesting position: MG1 should now be spinning backwards, as you can see from the table. Rotating backward, it causes the satellites to rotate forward. The rotation of the planets adds to the rotation of the carrier (from the internal combustion engine) and causes the ring gear to rotate much faster. Once again, the difference is that in the earlier case, we were happy to get more power with the help of high engine speeds, even moving at a slower speed. In the new case, we want the ICE to stay at a low RPM even if we have accelerated to a decent speed in order to set a lower power draw with high efficiency. We know from the section on power distribution devices that MG1 must reverse torque on the sun gear. This is, as it were, the fulcrum of the lever, with the help of which the internal combustion engine rotates the ring gear (and hence the wheels). Without MG1 drag, the ICE would simply spin MG1 instead of propelling the car. When MG1 rotated forward, it was easy to see that this reverse torque could be generated by the generator load. Therefore, the inverter electronics had to take power from MG1, and then reverse torque appeared. But now MG1 is spinning backwards, so how do we get it to generate this reverse torque? Ok, how would we make MG1 spin forward and produce straight torque? If only it worked like a motor! The opposite is true: if MG1 is rotating backwards and we want to get torque in the same direction, MG1 must be the motor and rotate using the electricity supplied by the inverter. It's starting to look exotic. ICE pushes, MG1 pushes, MG2, what, pushes too? There is no mechanical reason why this cannot happen. It may look attractive at first sight. The two engines and the internal combustion engine all contribute to the creation of the movement at the same time. But, we must recall that we got into this situation by reducing the speed of the internal combustion engine for efficiency. It wouldn't be an efficient way to get more power to the wheels; to do this, we must increase the ICE RPM and return to the earlier situation where MG1 is spinning forward in generator mode. There is one more problem: we have to figure out where we are going to get energy to rotate MG1 in motor mode? From a battery? We can do this for a while, but soon we will be forced to exit this mode, left without battery power to accelerate or climb the mountain. No, we must receive this energy continuously, without allowing the battery to run low. Thus, we came to the conclusion that the energy should come from MG2, which should work as a generator. Does generator MG2 produce power for motor MG1? Since both the ICE and MG1 contribute power that is combined by a planetary gear, the name "power combining mode" has been proposed. However, the idea of MG2 producing power for the MG1 motor was so at odds with people's ideas about how the system would work that a name was coined that has become generally accepted - "Heretical Mode". Let's go over it again and change our point of view. The internal combustion engine rotates the planet carrier at low speed. MG1 rotates the sun gear backwards. This causes the planets to rotate forward and adds more rotation to the ring gear. The crown gear still only receives 72% of the ICE torque, but the speed at which the ring rotates is increased by moving the MG1 motor backwards. Rotating the crown faster allows the car to go faster at low engine speeds. MG2, unbelievably, resists the car's movement like a generator, and produces electricity that powers MG1's motor. The car is propelled forward by the remaining mechanical torque from the internal combustion engine.
You can determine that you are moving in this mode if you are good at determining the engine speed by ear. You are driving forward at a decent speed and you can barely hear the engine. It can be completely masked by road noise. The Energy Monitor display shows the ICE engine's power to the wheels and the motor/generator charging the battery. The picture can change - the processes of charging and discharging the battery to the motor alternate in order to turn the wheels. I interpret this alternation as adjusting the MG2 generator load to keep the driving energy constant.
The future of the Toyota brand is hybrid cars. While electric vehicles are not perfect and move without recharging up to a maximum of 150 km. The batteries of hybrid vehicles are recharged by the internal combustion engine, providing comfort and economy when driving over any distance.
Hybrid car device
The device of a hybrid car (for example, Toyota Prius) is based on a series-parallel circuit. For such vehicles, the torque to the wheels can be supplied both from the motor and from the motor-generator. At the same time, the power of the units varies depending on the degree of charge and the capabilities of the motor.
The design is based on an internal combustion engine, an electric motor, two generators and a power divider. The latter device allows you to get under way and move at low speeds exclusively on an electric motor. The internal combustion engine at this point will only provide the operation of the generator.
The hybrid vehicle is charged by a separate alternator, so the electric motor-generator is only used to drive the drive wheels. During high loads, such as climbing uphill or driving at high speed, the gasoline engine is actively involved in the work. The power divider controls the transfer of torque from the internal combustion engine to the wheels, redistributing part of it to charge the battery and generator.
Working principle of a hybrid car
The principle of operation of a hybrid car (for example, a Toyota Prius) is as follows: the start, initial acceleration and driving at low speeds are provided by an electric motor-generator, and at increased loads, a gasoline engine is connected. The computer regulates its operation so that the highest efficiency rates are provided.
The power divider gear, which transmits torque to the drive wheels, is rotated by an electric motor. The main principle of operation of a hybrid car is to form the gear ratio of the transmission by a power divider, it is he who distributes the level of involvement in the operation of each of the motors.
Such a scheme of a hybrid car is called series-parallel. She combined all the advantages of series and parallel circuits. As a result, the engineers of the Japanese auto concern were able to create the most reliable unit, because the torque is controlled using electronics, excluding the participation of multiple mechanical components and mechanisms.
The regenerative braking system also transfers kinetic energy to the generator, replenishing the battery reserve. For emergency braking, a conventional friction braking system is used.
Engine (ICE) of a hybrid vehicle
The motor of a car operating on the principle of a hybrid is primarily based on the principle of efficiency. For the Toyota Prius, Toyota engineers were able to produce a 1.8-liter unit with a capacity of 98 horsepower. Now the Toyota Prius hybrid consumption is approximately 4.5 liters per 100 km (5 liters in the city and 3.9 liters on the highway). In the cold season, regardless of the driving mode, fuel consumption increases by an average of 2 liters per 100 km. For refueling, the manufacturer recommends using AI-95 gasoline.
It is worth noting that it will take a little more than 10 seconds to disperse the car to a hundred. In this case, the maximum speed of the car will be 180 km / h.
The Toyota hybrid engine type was selected in terms of maximum efficiency. In modern hybrids, it is 40%. Such indicators made it possible to obtain the use of a motor operating on the Atkinson cycle. The main feature of such a gasoline engine is that the compression of the fuel lags behind the piston stroke. It starts a little later than the start of the piston movement to the top of the sleeve. Thanks to this trick, some of the fuel-air mixture is returned to the intake manifold.
This type of internal combustion engine gave the modern Toyota Prius engine the following advantages:
- increase in the stroke of the piston;
- increase in efficiency;
- reduction in fuel consumption;
- optimal design for operation in a narrow range of revolutions of the crankshaft;
- 122 horsepower of the total power of the propulsion system.
Toyota car electric motor
Toyota Prius has two electric motors: control and traction motor-generators. Both engines are powered by batteries.
Traction motor-generator provides auto start and initial acceleration. The control motor generator is responsible for charging the hybrid vehicle and also acts as a starter.
As a rule, the Toyota Prius moves around the city in the start / stop mode solely due to the electric installation.
The power of the Toyota Prius electric motor is determined by the following characteristics:
- 60 horsepower;
- 56 kW;
- 163 N*m.
Recent Prius models have added the ability to charge from an electrical outlet, making them even more economical. Minus one - a full charge of the battery will be 6 hours, so while the use of a vehicle without the participation of an internal combustion engine is inconvenient for traveling long distances.
Accumulator battery
There are two batteries on board the Toyota Prius:
1. Auxiliary vehicle battery with a capacity of 45 Ah.
2. The main nickel-metal hydride high-voltage battery with a capacity of 6.5 Ah and a voltage of 201.6 V, consisting of 168 cells.
A feature of the device of the main battery of the car is that they are equipped with their own cooling system.
At one time, the Toyota Prius was a pioneer among hybrid cars. Today, hybrid installations have been improved so that they are also installed on other more massive Toyota models, nevertheless, the Prius is deservedly included in the ranking of the best hybrid cars. The popularity of such a motor scheme can be explained by its environmental friendliness, efficiency and reliability, proven over the years.
A used Toyota Prius can be viewed from two angles. On the one hand, it is a symbol of ecology, which has turned into an economical spineless car for traveling from point A to point B. On the other hand, it is an interesting and rather original way to reduce fuel costs.
But what do the vast majority of people really need? To make the car reliable, relatively fast, convenient, safe and consume a minimum of fuel. All these requirements are met by the third generation Toyota Prius.
The manufacturer claims that the Prius is able to get by with 4 liters of gasoline per 100 km. In reality, moving so as not to irritate others, you will need about 6 liters. If you avoid traveling on the highway, then in the city the average consumption will be about 5 liters. Outside the city, where the hybrid drive is no longer useful, and the engine has to push a car with heavy batteries, the cost will be at the level of 7-8 liters.
Practicality is another strong point of the Toyota Prius. There is quite a lot of space inside. But in terms of comfort, things are a little worse. Armchairs do not keep the body from moving, and the seat cushions are short. In addition, it is impossible to properly install the steering wheel. You either have to sit with your arms fully extended or with your legs bent.
You will have to get used to the extremely slow heating of the cabin in the winter. First of all, the engine with high thermal efficiency is to blame for this. The thermal energy it generates is simply not enough for such excesses as crew comfort. To save polar bears, something has to be sacrificed.
Even the ergonomics are not exemplary. The head-up display does not tire the eyes as much as the digital instrument cluster overloaded with small icons above the central panel. It takes time to get used to it.
Noise isolation and suspension are not bad in the city and at low speeds, but at a higher rate of movement, the tires begin to howl and the chassis makes itself felt. Rear axle with elastic beam, reacts boldly to cracks in the asphalt and undulating surfaces.
Toyota Prius does not require any special driving skills. But if you want to use the maximum potential of a hybrid setup, then you should get used to driving a little differently. For example, use inertia to accumulate electrical energy (recuperation). Thus, fuel can be saved. Having adapted to guess how far the hybrid can roll without gas, slowing down by inertia, it will be possible to use the brakes only in exceptional cases. This is a special kind of entertainment, no less exciting than riding sideways.
While earlier generations of the Prius could not rely entirely on an electric motor, the third generation of the model could well do without the help of an internal combustion engine. The power reserve is enough for 2-3 km of travel, but at speeds above 50 km / h, as a rule, the combined mode of the hybrid installation is activated.
The electric motor works mainly as an assistant, helping a relatively heavy car to start with dignity from a place. At intersections, few people want to stop for a hybrid. But what is the surprise of others when the Prius cheerfully starts at a green traffic light. Unlike some automatic machines that take forever after releasing the brake pedal before the car pulls away, the Japanese hybrid starts moving instantly. Of course, this is not the most economical way to ride, but you can always speed up if necessary. Toyota willingly accelerates somewhere up to 150 km / h, but after 130 km / h the acceleration is already a little impressive. On a flat road, a top speed of 180 km/h can be reached.
The hybrid power plant has three modes of operation. In the first, Eco - the response to the gas pedal is rather sluggish. And in Power mode, the reactions are too sharp and look like an ON / OFF switch. For ordinary trips, "standard mode" is better suited. Power might come in handy for overtaking.
The driving modes have no effect on the steering. The responses are a bit vague, as if the signals are being sent through wires. There is simply no feedback on the steering wheel. The Toyota Prius has a different character than classic cars. The driver can never become one with the Japanese hybrid.
At speeds up to 80 km/h, after removing the foot from the gas pedal, the engine is switched off and the energy recovery process begins. Braking occurs due to the electric motor, which saves brakes. There is also a transmission braking mode, which is necessary when driving down a steep descent with a loaded car.
Typical problems and malfunctions
Toyota Prius has no fatal defects. And the power drive is very reliable. The 1.8 liter internal combustion engine runs on a modified Atkinson cycle (the intake valve stays open for a while even when the piston starts to return, thus effectively simulating a variable length piston stroke).
Instead of the often problematic, limited-life CVT, a near-perpetual planetary gear is installed here. She works with an electric motor, which also does not have characteristic diseases. But this does not mean that the Toyota Prius does not require maintenance. A gasoline engine, like any other engine, regularly needs oil and filters to be updated. And after 300-400 thousand km, the gasket under the head of the block may burn out, or the cooling system pump may leak. Soon the EGR valve can fail. It is easily accessible from above and often comes to life after cleaning.
If there are any minor mechanical failures, then, as a rule, due to the neglect of regular maintenance. Problems also appear after long stops, during which the battery is completely discharged. This car should not be "idle".
The Toyota Prius went through a couple of big recalls. One concerned cars manufactured before January 2010 - there were problems with ABS on rough roads. In February 2014, the second one was announced. This time the repair required a hybrid installation. There was a danger of the inverter transistors overheating, causing the vehicle to go into safe mode or lose power completely. The defect affected all copies of the Prius and it is quite possible that this problem is still ahead of your car. The cost of a new inverter is from 320,000 rubles, used - from 20,000 rubles.
In winter, sometimes the central display begins to act up, not willingly responding to touch. Not too high-quality interior creaks at times, and plastic is easily scratched.
However, the reliability of the car is rated as above average. Toyota Prius regularly ranks first in satisfaction and reliability ratings.
Many people are concerned about battery life. It is true that in winter their capacity, and above all their readiness to move the vehicle on pure electric power, is reduced. But in a temperate climate, even after 100,000 km or 5 years of operation (warranty period), a significant decrease in battery power is not felt. Owners even after 300,000 km do not complain about the drop in battery capacity.
The need to replace a nickel-metal hydride (Ni-MH) battery may only arise after mechanical damage, such as an accident. The cost of a new high-voltage battery is from 280,000 rubles, a used one is from 45,000 rubles.
Maintenance
The oil in the gearbox and differential is designed for the entire service life and requires only a level and condition check every 60,000 km. Nevertheless, when operating in difficult conditions, Toyota recommends reducing the inspection interval to 45,000 km, and carrying out a complete replacement of working fluids no later than 90,000 km. Difficult conditions include frequent trips on the highway at a speed of about 130 km / h.
Still need to change the coolant. The first time after 150,000 km, and then every 90,000 km. The inverter coolant also needs to be updated: first after 240,000 km, and then every 90,000 km.
Conclusion
The third generation Toyota Prius is an extremely reliable car that, subject to the operating conditions and maintenance schedule, will not only be economical, but also durable.
Specifications Toyota Prius III (XW30 / 2009-2016)
Engine type - gasoline;
Working volume - 1798 cm3;
Type of timing system - DOHC;
Number of cylinders / valves per cylinder - 4/4;
Piston diameter / stroke - 80.5 mm / 88.3 mm;
Compression ratio - 13:1;
Maximum power - 100 kW (136 hp);
The highest torque - 207 Nm;
Acceleration from 0 to 100 km / h - 10.4 sec;
Maximum speed - 180 km / h;
Gearbox: type - stepless;
Fuel tank capacity - 45 l;
Weight: curb / full - 1495 kg / 1805 kg;
Fuel consumption:
Average / highway / city - 3.9 / 3.7 / 3.9 l / 100 km;
Wheelbase - 2700 mm;
Track: front / rear - 1525 / 1520 mm;
Tire size - 195/55 R15;
length × width × height - 4460 × 1745 × 1500 mm.
We deliberately stood in the toughest traffic jams, drove a circle around the Moscow Ring Road at night, counted every ruble spent and discussed the economic feasibility of the Prius.
The wheelbase of the new Prius is exactly the same as that of the old car. It turns out that the fourth generation hybrid is the result of a deep restyling?
It wasn't there! The fourth Prius is brand new. It is based on the TNGA (Toyota New Global Architecture) modular architecture, on which most of the company's models will be based in the foreseeable future. The share of high-strength steels in the body structure has increased from 3 to 19%, the torsional rigidity of the body has increased by 60% - this is with a curb weight reduced by 50 kg. Instead of a rear beam, the hybrid received an independent suspension, and the traction battery moved from the trunk under the seat. In fact, the former in the new Prius is only an internal combustion engine, and even that was noticeably improved. The Japanese managed to reduce friction losses and increase resistance to detonation. The thermodynamic efficiency of this engine is 40% - a record figure in the entire industry.
Claimed consumption in the region of 3 liters per 100 km - right? And why do the passport values of urban and suburban cycles practically do not differ?
Three liters per hundred, of course, is cunning. At least, we did not even manage to come close to these figures. The best result was 3.9 l / 100 km during the haul from Moscow to Dmitrov with an average speed of 55 km / h. The most "terrifying" values on the screen of the trip computer were 5.5 l / 100 km - however, to achieve such a result on the Prius, you need to ruthlessly "bludgeon". Under normal conditions, the consumption in the urban and suburban cycles is really almost identical and is about 4.3-4.5 liters per hundred. Thanks to the regenerative braking system, which works surprisingly efficiently in the city.
Is it possible to pay off the "hybridity" of the Prius due to low fuel consumption?
Let's figure it out together. As a starting point, let's take the Toyota Corolla sedan with a 122-horsepower 1.6-liter engine in the maximum Prestige configuration. Such a car costs 1,329,000 rubles and, in terms of consumer qualities, is as close as possible to the Prius (the same wheelbase and space in the back seat, the same power, a similar level of finish and equipment). The declared city consumption of a 1.6-liter Corolla in the city is 8.2 l / 100 km. On the highway - 5.3 l / 100 km. Of course, in reality, these values will be higher than stated. So let's take 9 l / 100 km as an average consumption, assuming that our hypothetical owner operates the car mainly in the city (recall, Prius consumption does not depend too much on the cycle and averages 4.5 l / 100 km). Thus, with an annual mileage of 25,000 km, the savings will be 1,125 liters, or 45,000 rubles (we equate one liter of AI-95 to 40 rubles). To compensate for the difference in price between the Corolla (1,329,000 rubles) and the Prius (2,112,000 rubles), it will take more than 17 years. Therefore, buying a hybrid in order to save money is utopian.
Then what's the point of it? What qualities can be written without a shadow of a doubt in the asset of the Prius?
The combination of handling and ride is commendable. The Prius handles even the toughest road imperfections perfectly and remains absolutely alive and fun to drive. Small rolls, rich feedback on the steering wheel. The Prius is also really quiet: you can’t hear the engine at all (unless you want to turn it into a cut-off), and the noise from the road penetrates the cabin only when driving on abrasive asphalt. Add a pleasant, well-finished interior. Plus, some will probably write down a flashy outrageous appearance as an asset to the “Japanese”.
Fine. But what about the obvious cons?
And here, many will also write down the appearance. After the price of more than two million rubles, this is perhaps the next deterrent. In addition, the Prius has a small trunk (only 276 liters according to our measurements). And if we talk about driving properties, the brakes are frustrating. An electric motor can unceremoniously intervene in the braking process at any moment, so that the effort on the pedals “walks”. More recently, I had the opportunity to experience a hybrid BMW X5 xDrive40e, which is devoid of such a feature. So, the father of all hybrids has something to strive for. Hybridity as such is no excuse.
What are the prospects for the fourth generation Prius in Russia?
I will be extremely careful in forecasts, but I have no doubt that the fourth Prius will become more popular than its predecessor. The fact is that for the whole of 2016 in Russia, only 16 third-generation hybrids were sold by official dealers. This is an absolute bottom, which the new product cannot break through. Believe it or not, I've even been lucky enough to see a fourth generation Prius on the road. Judging by the license plates, it belonged to a private individual, not to the Russian representative office of Toyota.
The hybrid car is not a new invention. The first step towards hybrid vehicles was taken in 1665 when Ferdinand Verbiest, a Jesuit priest, began work on plans for a simple four wheeled vehicle that could be powered by steam or horse drawn. The first cars with a hybrid engine appeared at the turn of the 19th and 20th centuries. Moreover, some developers have managed to move from projects to small-scale production. Starting in 1897 and over the next 10 years, the French Compagnie Parisienne des Voitures Electriques produced a batch of electric and hybrid cars. In 1900, General Electric designed a hybrid car with a 4-cylinder gasoline engine. And the "hybrid" trucks left the assembly line of the Walker Vehicle Company of Chicago until 1940.
Of course, all these were only prototypes and small-scale cars. Now, however, an acute shortage of oil and the economic crisis have spurred the development of hybrid engines. Now let's take a closer look at what a hybrid engine is and what is the use of it? A hybrid engine is a system of two engines - electric and gasoline. Depending on the operating modes, both petrol and electric can be switched on simultaneously or separately. This process is controlled by a powerful computer, which decides what should work right now. So, when driving along the tracks, the gasoline engine is turned on, since the battery on the track will not last long. If the car is moving in urban mode, then an electric motor is already used here, both of them work during acceleration or heavy loads. While the petrol engine is running, the battery is being charged. Such an engine, even taking into account the fact that the system uses a gasoline engine, can reduce harmful emissions into the atmosphere by 90% and at the same time, gasoline consumption in the city is significantly reduced (only a gasoline engine works on the highway, so there is no savings there). 
Let's start with how the car moves off. At the beginning of the movement and at low speeds, only the battery and electric motors are involved. The energy stored in the battery goes to the energy center, which, in turn, sends it to the electric motors, making the car move smoothly and silently. After picking up speed, the internal combustion engine is connected to work, and the moment on the drive wheels is supplied simultaneously from electric motors and internal combustion engines. In this case, part of the energy of the internal combustion engine goes to the generator, and now it feeds the electric motors, and gives off the excess of its energy to the battery, which has lost part of the energy reserve at the beginning of the movement. When driving in normal mode, only front-wheel drive is automatically used, in all others - all-wheel drive. In the acceleration mode, the torque to the wheels comes mainly from the gasoline engine, and the electric motors, if necessary, increase the dynamics, complement the internal combustion engine. One of the most interesting moments is braking. The electronic “brains” of the car decide for themselves when to apply the hydraulic braking system, and when regenerative braking, giving preference to the latter. That is, at the moment the brake pedal is pressed, they transfer the electric motors to the “generator” mode of operation, and they create a braking torque on the wheels, generating electricity and feeding the battery through the energy center. This is the highlight of the “hybrid”. 
In classic cars, braking energy is completely lost, leaving as heat through the brake discs and other parts. The use of braking energy is especially effective in urban areas, when you often have to brake at traffic lights. Vehicle Dynamics Integrated Management (VDIM) integrates and manages all active safety systems.
One of the first successful cars equipped with a hybrid engine that went to the masses was the Toyota Prius developed by Toyota, which consumes 3.2 liters of gasoline per 100 km (in the city). Toyota also released an SUV with a Lexus RX400h hybrid engine. The cost of such a car, depending on the configuration, ranges from 68 to 77 thousand dollars. It should be noted that the first versions of the Toyota Prius were inferior to cars of the same class both in speed and power, but the Lexus RX400h is no longer inferior to its classmates in either speed or power. 
The world's leading automotive concerns have also turned their attention to hybrid engines as a solution to the problem of fuel economy and environmental pollution. So the Volvo Group announced the creation of a hybrid engine for trucks, tractors, semi-trailers and buses. The company's developers expect that their brainchild will allow you to get 35% fuel savings.
With all this, it must be said that hybrid cars "with a bang", so far, have gone only in North America (Canada and the USA). And in America, the demand for them is growing more and more, since until recent years cars that consumed a lot of fuel were popular there, and since fuel began to rise sharply and steeply in price, the Americans sharply thought about saving it and, as a solution to the problem, they began to use cars with hybrid engines. In Europe, the appearance of hybrid engines was taken calmly, since there they drive an economical and more environmentally friendly than a gasoline engine, the good old diesel. Unlike the USA, more than 50% of cars in Europe are equipped with diesel engines. In addition, diesel cars are cheaper than hybrid cars, simpler and more reliable. After all, everyone knows that the more complex the system, the less reliable it is! And precisely because of their complexity and capriciousness, there are practically no hybrid cars in the post-Soviet space. Official dealers do not bring them here. And any owner of such a car will inevitably face the problem of service stations. We do not have service stations that would deal with hybrid cars. And you can’t fix such a machine yourself!
