Fig. 2.1. Diagram of dynamic characteristics of Mazda 3 engines
The Mazda 3 is equipped with modern new generation engines with improved dynamic and maintainability characteristics. The L8 engine has a displacement of 1.8 liters, max. power - 88 kW (120 hp), max. torque - 165 N·m / 4300 min⁻¹ developing a maximum speed of 197 km / h. The LF engine has a displacement of 1.8 liters, max. power - 104 kW (141 hp), max. torque - 181 N·m / 4100 min⁻¹ developing a maximum speed of 208 km / h. The L3 engine has a displacement of 2.3 liters, max. power - 122 kW (166 hp), max. torque. torque – 207 N·m/ 4000 min⁻¹, developing a maximum speed of 214 km/h. The L3 engine can be equipped with a turbocharger – the Sequential Valve Timing (S-VT) system. The principle of operation of the turbocharger is that the turbocharger drive works due to the energy of the burnt exhaust gases. The compressor consists of two axial blade wheels. Hot exhaust gases enter the turbocharger housing, where they spin the working (first) wheel to a rotation speed of 100,000 min⁻¹. The working wheel, in turn, spins the second blade wheel by means of a shaft, which pumps air into the compressor and delivers it to the combustion chamber. The heated air that has passed through the turbocharger is cooled in the intake air radiator. It is cooling that provides a greater increase in power (Fig. 2.1).
Fig. 2.2. General view of the Mazda 3 engines
Mazda has made a number of technical improvements to the design and technical components of the new engines.
For example, the L3 engines use a variable valve timing mechanism. In order to reduce the overall weight of the vehicle, the cylinder block on the new engines is made, like the cylinder head, from an aluminum alloy.
Major changes have been made to the design and mechanical parts of the engines in order to reduce vibrations and noise levels. For example, a cassette-type balancing unit is used on the L3 engines. All engines are now equipped with a silent timing chain. The cylinder block is equipped with a long piston skirt and an integrated main bearing cap. In addition, all engines use a crankshaft pulley with a torsional vibration damper and a pendulum-type suspension.
The auxiliary drive belt circuit has been simplified to improve maintainability. Now a single drive belt is used for all auxiliary engine units. The drive belt tension is adjusted by an automatic tensioner. The front engine cover has a service opening (to release the chain adjustment ratchet and lock the tensioner lever).
The Mazda 3 cars use 4-cylinder engines as a power plant, in which the cylinders are located in one row. The engine is covered from below by a sump, forming a crankcase, which is also a reservoir for oil, which is necessary for lubrication, cooling and protection of engine parts from wear.
All three engines are 16-valve, with four valves per cylinder. The valves are actuated by two overhead camshafts via plate tappets.
The engine is lubricated by an oil pump mounted on the end face of the crankcase and driven by the crankshaft. Oil sucked from the oil pan is supplied through holes and channels to the crankshaft and camshaft bearings and to the working surfaces of the cylinders.
The preparation and supply of the fuel-air mixture is carried out by an electronic engine management system that does not require maintenance.