![]() ![]() The A25A-FKS features the Dual Variable Valve Timing system (DVVT). The intake and exhaust camshafts are driven by low-friction single-row timing chain with a pitch of 8.0 mm. The engine is equipped with hydraulic tappets for continues zero valve clearance. The valves are actuated by camshafts via roller rocker arms. ![]() The intake port has a laser-cladded valve seat while the exhaust has a normal pressed valve seat. The angle between the intake and exhaust valve is 41 deg. The engine has an aluminum 16-valve cylinder head with two chain-driven camshafts in separate casing at the top. The main innovation is the second generation variable-pressure oil pump controlled by ECM electronics. The pistons are cooled with engine oil sprayed by two oil jets for each piston. The upper compression and oil rings have a DLC coating (Diamond Like Carbon). The engine got the high-strength connecting rods and lightweight aluminum T-shape pistons with a special resin coating. That gear on the crankshaft drives the balancing unit attached to the engine block at the bottom. The crankshaft has 7 traditional counterweights and one with tooth gear. The longitudinal axis of the crankshaft has a 10 mm offset against the axes of the cylinders. Toyota continues to refrain from charging by turbo or compressor.The A25A engine has a new open-deck aluminum alloy cylinder block with sleeves cast directly in block material. The standard engine achieves 205 hp and 250 Newton meters of torque, the hybrid variant reaches 178 hp and 221 Newton meters. As before, the new direct injection engine is available in two designs for use as the sole drive sourceand manufactured as a hybrid version in conjunction with an electric drive. The consumption of the new four-cylinder is said to be 16 percent lower than its predecessor, and the acceleration time to be ten percent. Thanks to the variable valve control, the engine can also be operated in the Atkinson cycle, depending on requirements. As already shown with other engines in Vienna at the engine symposium, Toyota also relies on an electric water pump, which not only works more effectively, but is also intended to considerably shorten the pollutant-rich warm-up process of the machine. The engine has a new electrical system for variable valve control, a new direct injection system (D-4S) with multi-hole injector and a variably controllable cooling and lubrication system. ![]() The engine's intake valve seat is manufactured using the so-called laser cladding process together with the new piston design, the wobble ratio and the air flow coefficient are to be increased. The basic structure such as the stroke-to-bore ratio and the valve structure have been completely redesigned, with 87.5: 103.4 the 2.5-liter engine is once again significantly longer than its predecessor. In order to achieve the higher specific power with lower fuel consumption and exhaust emissions, the combustion system was fundamentally modified. The latter also explains why the 2.5-liter engine is the first to come - in both the hybrid and the regular combustion version, it is the most popular engine in Toyota's bestseller Camry.Ĭompared to the the latest generation of engines, the new TNGA four-cylinder should achieve a thermal efficiency of over 40 percent. ![]() The 'Dynamic Force Engine' series is part of the new TNGA platform strategy that comes with the new Prius, the C-HR and the Camry presented in Detroit in January already includes three models. It starts with a four-cylinder with a displacement of 2.5 liters, which Toyota has now presented in detail at the Vienna Motor Symposium. Instead, the engineers focused on a new family of gasoline engines that will include 17 variants of nine different engines at the end of the development program. In Europe, they are cooperating with BMW on diesel engines, while Toyota has stopped all development work on passenger car diesel engines for the remaining markets. F or for Toyota, the diesel issue is over in the long run. ![]()
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