The evolution of automotive engines since the early 90s

    The basis of the modern car is its internal combustion engine (ICE), and despite the development of alternative energy sources, the traditional ICE retains its superiority due to cultural, economic and social reasons. From 1994 to 2008, automobile engines underwent many changes and improvements, which had a positive effect on its economic and environmental performance. It is possible to understand the logic of the development of ICE on the basis of trends and patterns of global scale for a certain period of time. Since the beginning of the 90s, radical changes in the design have occurred in the automotive industry due to new materials and new requirements for a “global” car.

    The change in the ratio of diesel to gasoline models over a period of 15 years has contributed to an increase in the use of diesel cars in the world, although this process is uneven, and has largely affected Western Europe, where the fleet of diesel cars in some countries grew from 25% to 70% . The diesel engine, possessing higher fuel efficiency as compared with gasoline engines, has certain disadvantages: reduced specific power, relatively high noise level, it is difficult to reduce toxicity of exhaust gases, higher production cost. Therefore, the final choice between a gasoline and diesel engine for a passenger car is still controversial. Quite possible, that the impact of environmental standards and fuel economy requirements of automobile engines over the next 10-15 years will lead to technical convergence of gasoline engines and diesel engines with a simultaneous reduction in the difference in fuel consumption and the cost of production of these types of engines. This is evidenced by the development of DaimlerChycler in the concept of the Mersedes Benz F700 with the engine, which implements the compression of gasoline, as on a diesel engine, which brings it closer to diesel engines in terms of efficiency, due to the use of a more advanced thermodynamic cycle. All modern technologies of the decade are implemented in this engine: direct injection, controlled turbocharging, variable compression ratio and other recent developments ensuring fuel consumption of 5 liters / 100km for a relatively big car.

    For the period of 15 years, the Downsizing philosophy has been strengthened in modern engine building, which suggests that it is better to get more power from a smaller volume than from a larger one, since this opens up prospects for reducing the weight and size of the power unit, as well as improving fuel efficiency in modes idling and partial loads. This modern thinking launched the process of reducing the volume and number of engine cylinders, and now even the basis of automobile engines - the 4-cylinder ICE began to reduce the working volume and undergo modernization towards the “working volume on demand” technology, which essentially turns these engines into 2- x cylinder. The engines of recent years have become more diverse in the number of layouts in the engine compartment: W, VR and V-shaped circuits with a different angle of block collapse have appeared, as well as inline engines with an odd number of cylinders, but all these schemes in general had no effect on the bulk of the layouts and only diversified engine building. The basis of the internal combustion engine is still the engine R layout.

    The fuel delivery system has also changed a lot. The era of carburetor systems and engines with central injection has passed, and it is replaced by a distributed injection and a direct one. At the turn of the century, a new development of fuel injection systems began, based on the use of fundamentally new electronic direct fuel injection systems, and their use is increasing, despite the complexity and demands on the quality of fuel from these engines. Most of the internal combustion engines of modern design still use distributed injection, which will continue to be improved, improving the regulation of vortex formation at the inlet and the quality of fuel atomization, since there are considerable possibilities in this, taking into account the development of technology.

    The diesel fuel injection system has also evolved lately. For diesel engines, the most important factor determining the performance of the workflow is the used scheme of mixing. The use of diesel engines in passenger cars began with pre-chamber and vortex-chamber structures (split combustion chambers). However, as a consequence of a number of fundamental flaws in these blending schemes, as well as due to the development in the field of diesel engines with unseparated chambers, in recent years there has been a tendency to use direct fuel injection. The development of direct injection was influenced by the development of the Common Rail fuel injection system, which made it possible to expand the range of modifications and models of engines with a diesel engine. Further development of the Common Rail system is associated with a further increase in fuel pressure in the fuel rail (180 ..

    Under the influence of the threat of depletion of oil resources and the tightening of environmental standards for internal combustion engines, the majority of auto concerns in developing new models set the priority task of high fuel efficiency and environmental friendliness. Power indicators are now ranked third in the list of priorities (with the exception only for sports models). That is why the power of mass cars is not growing as much as before the early 90s. Changes in the gas distribution system in recent years shows that the 4-valve scheme is becoming a standard for cars because of its obvious advantages, and 3 and 5-valve remain a rare exception to the rule. The number of cars using supercharging engines is also growing. The basis of modern supercharging is turbocharging in various variations as well as in combination with mechanical supercharging. Should notice that almost all engines with distributed petrol injection have tuned intake pipes providing gas dynamic boost. At the same time, pipelines with variable geometry are being increasingly used to achieve optimal intake settings for various operating conditions. The use of turbocharging is particularly pronounced on diesel engines, and with the development of pressurization technology, charge air coolers (intercoolers) were used to increase efficiency. Now the use of intercoolers has become the rule for most supercharged engines. allowing to achieve the optimal setting of the intake at different operating conditions. The use of turbocharging is particularly pronounced on diesel engines, and with the development of pressurization technology, charge air coolers (intercoolers) were used to increase efficiency. Now the use of intercoolers has become the rule for most supercharged engines. allowing to achieve the optimal setting of the intake at different operating conditions. The use of turbocharging is particularly pronounced on diesel engines, and with the development of pressurization technology, charge air coolers (intercoolers) were used to increase efficiency. Now the use of intercoolers has become the rule for most supercharged engines.

    The potential of the engine for the period from the 90s to our time is mainly trying to expand by increasing the efficiency of idling and partial loads, which constitute the bulk of the time a modern car is used. The valve timing control system that regulates the opening and closing phases of the intake and exhaust valves using phase shifters mounted on the camshafts has found wide use. The first models of phase shifters were mainly hydraulic, and regulated the operation of the intake valves, but the latest models are already electric, which increases speed and efficiency, and also they regulate both the inlet and outlet valves. The disadvantage of phase control with phase shifters installed on the camshaft was a step change in valve timing, which was the reason for developing systems for smooth control of valve timing. The first such system was Valvetronic from BMW, which regulated the phases by continuously adjusting the change in the lift height of the intake valves (thanks to this system, it was the first time that a gasoline engine was created without a throttle valve!). Soon, similar technologies were mastered by Nissan (VVEL) and Toyota (Valvematic). But the most advanced development was presented by FIAT under the name MultiAir. In the MultiAir system, one camshaft is used for intake and exhaust valves, and the intake action of the cams occurs through a special electro-hydraulic system that allows you to control the inlet of each valve individually.

    Modern automobile engines have now become more perfect thanks to new materials in their manufacture and a deeper miscalculation and study of the processes occurring in the internal combustion engine, which has resulted in reducing friction losses and pumping losses inside the engine. The introduction of the principle of changing the power of the engine drive units, depending on the need, reduced the energy costs of driving the oil pump and the engine's water pump, and also turned off the generator during acceleration and turned on when braking, depending on the possibility and need for this.

    The period from the beginning of the 90s to the present day can rightly be called the period of transition from the complex mechanical structures of symbiosis of various technologies to the electrification of all possible auxiliary units in a car to achieve the greatest energy efficiency.

    PS If you briefly describe the essence of everything described above, it’s about the fact that the number of implemented technologies for the first time since the 90s did not increase the capacity of the car several times, but only allowed to achieve a number of intermediate goals. It was the subsequent transition to the introduction of electrical components in the internal combustion engine gave a qualitatively better result, without complicating the design, while achieving the same goals as the mechanic-hydro-pneumatic systems in the internal combustion engine.

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