Category: New cars

Selection Fruits

2023
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Selection Fruits
Selection Fruits
Anonim

EQUIPMENT

VIRTUAL DUEL: Toyota Prius - Honda Insight

FRUITS OF SELECTION

MAXIM NETS

It will take a lot of time until cars with a “zero exhaust” - for example, hydrogen-powered cars - finally displace the ancestors with gasoline and diesel engines. In the meantime, produce transitional products - the so-called hybrids. An electric motor works in conjunction with an internal combustion engine: it gives an increase in power and torque, helps to save fuel and significantly improves environmental performance.

The number of such models is growing. In our virtual duel, the two founders of the hybrid movement came together. Toyota Prius lives already in the second generation - the first version debuted in 1997, becoming the pioneer of serial hybridization in the world.

Two years later, Honda Insight came out. The concepts of Japanese cars are generally similar, but implemented in different ways.

IN THE KINGDOM OF INTERNAL COMBUSTION

The one and a half liter Toyota gas engine developed specifically for the Prius operates according to the Atkinson cycle. The geometric compression ratio of 13.5 compared to many engines with the traditional Otto cycle is very high. To prevent destructive detonation, the inlet valve is closed much later than the bottom dead center, "spitting out" part of the fresh charge back to the intake manifold. It turns out that to compress the mixture, the piston uses only part of its stroke, and on the expansion stroke - all. This is beneficial in terms of the completeness of combustion of the mixture and allows you to get the best environmental performance and efficiency.

The valve timing is regulated by the VVT ​​system known for other Toyota motors. Depending on the load and revolutions, the control unit calculates the optimal valve opening and closing times and issues a command to the hydraulic rotary devices that rotate the camshafts. For the Prius engine, the designers made the pistons as light as possible, picked up the valve springs with optimal stiffness, and installed an exhaust system with minimal back pressure. Most of the design solutions, of course, passed from its predecessor - the first generation motor. The new engine is controlled by a computer with a 32-bit processor.

Honda, while developing the engine for Insight, also focused on fuel economy and ecology. The designers tried not only to find high-tech materials in order to reduce the total weight of the unit and friction losses, but also to reduce the number of parts. For example, a multi-valve design (four per cylinder) costs one camshaft in the bed of the block head. By the way, rollers were installed on the rocker arms to reduce friction, and an antifriction coating was applied to the piston skirts. The developers claim that in this way the power loss was reduced by 30%. To facilitate the design, the oil sump, as well as the body of the control units, were made of magnesium alloy, which is about a third lighter than aluminum. Some engine parts, in particular the intake manifold and the head cover, are made of composite materials.

The dynamic characteristics of the Honda engine are improved by the VTEC phase control system. To implement "in the iron" many interesting decisions made and ecology. For example, an exhaust manifold is integrated with a block head. Exhaust gases warm up the converter faster, which means that when cold-launched, harmful emissions pollute the atmosphere less. The non-separable design allowed to win in weight. In addition, to save fuel at low and medium power modes, the engine runs on lean mixtures, during the combustion of which nitrogen oxides are released. Trapping them is a matter of an additional NOx converter.

PLUS Kilowatts

A 57 kW gasoline engine alone could not provide decent dynamic performance for the Prius. Paired with it is a 50-kilowatt AC electric motor. Unlike the first-generation hybrid installation, here the electric motor plays no longer an auxiliary, but a leading role. The car starts on electric traction even with a fairly dynamic acceleration. The gasoline unit comes into operation much later. At medium speeds and in some modes - mainly when the internal combustion engine is operating in a sub-optimal speed range, the electric motor also takes on the main load.

It is curious that the driver, by pressing the EV button (Electric Vehicle) on the instrument panel, can set the mode in which the internal combustion engine does not turn on at all. With fully charged batteries, the Prius only drives “on electricity” up to 2 km at a speed of no more than 50 km / h.

The hybrid Toyota has no gearbox as such. Electric and gasoline engines, as well as the starter-generator are connected by a planetary gear, the moment from which goes to the wheels through the gearbox (ratio 4.11: 1). The control unit coordinates the operation of the transmission, giving commands to the planetary gear actuators, which slows down the necessary gears.

Honda follows a different pattern. An electric motor with a power of 7 kW only helps the internal combustion engine and does not work alone. Like the Prius, the gasoline engine stalls at stops, without wasting fuel and polluting the atmosphere. To let it in, just squeeze the clutch and engage first gear.

Honda’s brushless AC motor is more compact and lighter than Toyota’s. A narrow 60 mm case is installed between the engine and gearbox (optionally a five-speed manual or CVT). During acceleration, the electric motor tightens the crankshaft, and when braking it acts as a generator, converting mechanical energy into electrical energy and giving current to the metal hydride battery located in the floor behind the seats. In terms of capacity and dimensions, it is smaller than that of the Prius. But the Toyota electric motor is several times more powerful. But, unlike the Prius, when the electric motor fails, the Insight can be driven by a gasoline engine.

SWEEP ECONOMY

One of the main tasks that the developers of the hybrids set for themselves was to make cars neither in appearance nor in dynamic qualities different from “normal” cars. The hybrid should stand out for its environmental friendliness and low fuel consumption. According to the calculations of Honda, the share of the hybrid unit accounts for approximately 65% ​​of gasoline saved. And where are the remaining 35%?

The developers of Insight tried to lighten the car as much as possible. They were able to remove the extra pounds not only from a compact power unit. The two-seater body is aluminum, with the exception of some parts from almost weightless composite materials. A steel “dress” would be almost 40% heavier.

Toyota engineers also understood: overweight is wasted liters of gasoline. Therefore, the “body” was also made “hybrid” from high-strength lightweight steel, aluminum and composite parts. Of course, the phenomenal results of the Honda Toyota could not be achieved. However, do not forget that Insight is smaller, and there are only two seats in the cabin, and there are five in the Prius.

In the development of bodies, of course, great attention was paid to aerodynamics. "Licked" everything that is possible, and the bottoms of the cars made completely flat. On the "Insight" even closed the rear wheels with shields. Result: Cx “Honda” - 0.25, “Toyota” - 0.26.

Narrow tires with low rolling resistance help save gas. Particularly unusual is the size of the Prius shoe. Hybrid power steering - electric. They do not take away excess forces from the engine and do not waste precious precious fuel. For the same reason, the Prius air conditioning compressor is also driven by an electric motor.

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