One of the disadvantages of spark ignition engines, whose power is regulated by throttling, is the increased fuel consumption at low loads and when the engine is idle. The combined method of engine power regulation by switching off the cylinder group and throttling working cylinders is one of the effective ways to improve fuel economy in the above-mentioned modes. This article presents the research results of the combined method of engine power regulation which can be realized by minor structural changes in operating conditions. The method implies the following: at low loads and at idle speed of the engine. Fuel supply to the group of cylinders is switched off with the simultaneous increase of the cyclic fuel supply in the working cylinders. The adequacy of the calculated results has been checked by the indication of operating processes in switched off and working cylinders. The research results of a six-cylinder spark ignition engine with the distributed gasoline injection using the combined power regulation system have been shown. The angles of opening the throttle which provides a non-shock transition from the operation with all cylinders to the operation with the cylinder group switched off have been determined.

A major issue with spark-ignition engines is their fuel inefficiency and negative environmental effects, especially in urban driving situations. This topic is of utmost importance considering the increasing apprehension over environmental contamination and the need for enhanced energy efficiency. The research’s originality resides in its strategy to tackling this issue without necessitating intricate engine changes, a manner not commonly used. The research uses a dual strategy that integrates both theoretical and experimental approaches. The theoretical component entails developing models to forecast the effects of different cylinder deactivation strategies on fuel consumption and emissions. Important factors to address in this theoretical model are the introduction of air into cylinders that are not in use and the stopping of fuel supply. The experimental component involves conducting bench experiments on a modified spark-ignition engine to verify the theoretical conclusions. These tests assess performance metrics, such as fuel economy and environmental effect, under different load situations. The study’s findings are encouraging. The study reveals that disabling a specific group of cylinders while permitting unrestricted air intake might result in significant improvements in fuel economy, anywhere from 1.5% to 10.5%, depending on the engine’s workload. Bench testing revealed a maximum improvement of 10.8%, which demonstrates the efficacy of this strategy. The study’s findings indicate that the use of the integrated power regulation approach greatly improves fuel efficiency and decreases the impact of the environmental consequences of spark-ignition engines, especially in situations of low load and idling. This technology demonstrates its feasibility as a solution that can be seamlessly incorporated into current engine designs with few adjustments, providing a practical and environmentally responsible option for enhancing vehicle performance. The results indicate that this approach has wide-ranging potential uses in the automotive sector, particularly for urban cars that often function in situations with modest levels of demand. By using this approach, manufacturers may attain enhanced fuel efficiency and diminish emissions, this contributing to the development of more sustainable urban transportation options.

The chapter focuses on the use of the combined thermal development system with phase-transitional thermal accumulators. The peculiarity of the combined system is that it uses thermal energy of exhaust gas, coolant and motor oil for rapid pre-start and after-start heating of the vehicular engine. The structure of the combined thermal development system and a mathematical model have been developed to study the impact of the system parameters on the heating processes of the engine. The results of experimental and estimation studies of thermal accumulator materials and the combined heating system of the vehicular engine are shown. For a truck engine 8FS 9.2/8, it is shown that the use of the combined system reduces the time of coolant and motor oil thermal development by 22.9–57.5% and 25–57% accordingly compared with the use of a standard system. The peculiarities of forming and using the system depend on operational and climatic conditions and the category of the vehicle.

The article presents the results of the oretical studies on the impact of methods for improving the energy characteristics on the fuel economy of a spark ignition engine with feedback and a three-way catalytic converter under full load conditions. Various methods for improving the energy characteristics of spark ignition engines to achieve high energy efficiency are known. The most commonly used method is enriching the fuel-air mixture under full load conditions. However, this method has several drawbacks, including reduced fuel economy and inefficient operation of the catalytic converter. Another known method for improving the energy characteristics of spark ignition engines is by adding oxygen-containing gases, particularly nitrogen oxide, to the air charge, where oxygen by volume constitutes 33%, significantly higher than in air (21%). This method is widely used for boosting the performance of sports car engines. However, there is a lack of research on the impact of this method on fuel economy compared to the enrichment method in the literature. Improving the fuel economy of the engine without deteriorating the energy characteristics is possible by transitioning from operating on enriched fuel-air mixtures to operating on a stoichiometric mixture by adding nitrogen oxide to the engine's air charge. This task was addressed in the article through calculations using experimental data. Fuel economy was evaluated by comparing the specific effective gasoline consumption determined by the engine's work when using an enriched fuel-air mixture and adding nitrogen oxide to the air charge to regulate it to a stoichiometric mixture. It was shown that using nitrogen oxide additives to the engine's air charge can improve fuel economy and increase engine energy characteristics compared to the method of enriching the fuel-air mixture.

The article considers ways to evaluate the influence of various implementations of the combined method of power regulating of the engine with spark ignition on mechanical losses and fuel economy. The object of research is a method of power regulating of a spark-ignition engine. The purpose of the study is to evaluate different ways to improve the combined method of power regulating of a spark-ignition engine. A theoretical study of various implementations of the combined method of power regulating of the engine with spark ignition. The study took into account the results of previous studies in this area. According to the results of this study, it is established that when the group of cylinders is deactivated with free air intake, mechanical losses can be reduced and fuel efficiency can be improved by 5...11% in comparison with disabling only a fuel supply with unchanged gas exchange system . KEY WORDS: CYLINDER DISCONNECTION, FUEL ECONOMY, POWER ADJUSTMENT