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.Energies 2020, 13, 1076 2 of 19 forced idling. In this case, most of the time cars move at a low speed, with the engine running at low loads and at idle speed.Operating modes of automobile engines under operating conditions have been investigated in many papers. At low speed and low load, high heat transfer and combustion losses occur, directly affecting engine operating conditions [1]. In most cases, these actual engine operating conditions are not reflected in standardized driving cycles and, sometimes, summaries of experimentally-derived cycles are also used to evaluate traffic jams [2]. Design changes, such as ceramic-coated engines, have also been used to reduce heat loss, which, when used in combination with biodiesel as fuel, have shown optimum engine operating conditions [3]. This effect is also noticeable when using triglyceride-based biodiesel as fuel [4]. Hydroxyl gas can also be used as an indicator to improve engine natural conditions, resulting in higher thermal efficiency and improved exhaust emissions [5]. The possible use of biobutanol as another source of biofuels and similar trends in engine operating conditions due to its higher oxidative stability [6] as a spark ignition [7], as a compression ignition engines [8]. It is also known that the use of alcohol additives in petrol improves its properties and achieves an ecological effect [9]. The EGR system shows a different reduction in cycle pressure [10] which is noticeable when operating small engines [11]. Studies [12][13][14][15] shows that the basic operating modes of both freight and passenger vehicles moving in cities are part speed and loading modes. They involve acceleration, steady mode, and active and forced idling while driving and braking the car. Most of the time the vehicular engines run the open throttle or with a fuel s...