Section 4. Responding to the Oil Crisis
Item 6. Development of LASRE Engines
As a result of conducting research and development on technologies for cleaning emissions, substantial progress was made on engine technologies including combustion and control technologies. At the same time, emissions countermeasures resulted in deterioration of vehicle performance and fuel efficiency, and demands from the market to restore performance and efficiency were rising.
As a modernization advanced, the focus of passenger car use shifted from taxi users to personal users. Vehicles used as taxis have to be durable and not prone to breaking down, but individual users demand cars with good response, maneuverability, and minimal maintenance burdens.
It was against this backdrop that Toyota adopted "manufacture of appealing products" as a corporate policy in 1978 and began developing engines that complied with emissions regulations while improving drive performance and fuel efficiency. New engine development started with compact size and lightweight, high-performance, high fuel efficiency, quiet ride, good responsiveness, and low maintenance as the main design parameters.
New engine technologies and mechanisms relating to the emissions policies at that time, high fuel efficiency, and high output are as shown in the diagram below.
The key to making engines smaller and lighter is achieving the design limits of each engine component, and accordingly, each component that makes up the engine was individually re-examined. The reductions in engine weight achieved through this process generated significant ripple effects, such as reduced burdens on the body, leading to improved acceleration response and higher fuel efficiency.
Basic research and analysis on combustion that had reached the level of elucidating conditions within the combustion chamber as a result of emissions countermeasures were used to vastly improve the configuration of the combustion chamber as well as the intake and exhaust systems and the fuel supply system. In addition, new mechanisms such as the timing belt and a hydraulic valve lash adjuster were adopted to reduce noise and maintenance.
The six-cylinder 1G-EU engine developed through this process was first used on the new Cresta in April 1980. Even though the engine had six cylinders it weighed only 154 kilograms, lighter than the 171-kilograms four-cylinder 21R-U engine in the same class.
The four-cylinder 1S-U engine (1,832 cc, 100 hp) was completed in July 1981. The combustion chamber was improved, various components were made considerably lighter, and a finite element analysis technique and laser holography were used to create new vibration countermeasures. The engine also incorporated numerous new components such as sintered hollow camshafts and sintered and forged connecting rods developed through the use of state-of-the-art production technologies.
With the completion of the 1S series engines, Toyota planned a technology campaign to give this series of new engines-which were developed to meet the demands of the times-common names and to publicize them to users. The name selected from among many proposals was LASRE. The name was derived from the first letters of lightweight, advanced, super response, and engine. This was the first time in Japan that an engine was made into a product brand. In the second half of the 1980s and later, the LASRE engine series adopted on new vehicles made significant contributions to Toyota's corporate image.