Toyota Motor continues its research for maximizing engines’ thermal efficiency and recently, the Toyota revealed two new improved engines. They are small and are said to be at least 10% more fuel efficient over the current ones. Toyota revealed a new 1.3- and 1-liter gasoline engines with improved combustion and loss-reduction technologies. The units are said to be used in the near future on redesigned vehicles, along with 12 other new engine variations which will be introduced globally by 2015.
1.3-liter Atkinson cycle
The first one is 1.3-liter four-cylinder using the Atkinson cycle, which is normally used in dedicated hybrid engines. By fitting it with the Atkinson cycle, the gases expansion ratio is increased and the heat waste is reduced through a higher compression ratio (13.5), resulting in a superior overall thermal efficiency. Further fuel efficiency is assured via using a reshaped intake port that generates a strong tumble flow inside the cylinders as well as a cooled exhaust gas recirculation (EGR) system paired with Variable Valve Timing-intelligent Electric (VVT-iE) technology. As a result, the new engine will have a thermal efficiency of up to 38 percent (top of the industry) and paired with start-stop and other functions, it will also lead to a 15 percent fuel consumption improvement.
1-liter
The other engine is a 1-liter gasoline unit co-developed with Daihatsu Motor Co., Ltd. which managed to achieve a maximum thermal efficiency if 37 percent. The engine uses a similar tumble flow-generating intake port, a cooled EGR system and a high compression ratio. It will also use start-stop and other functions which will aid it to achieve a maximum fuel consumption of around 30 percent over the current version.
