Toyota Next-Generation Lean-Burn Engine Arrived in 1992

Did you know that in May 1992, TOYOTA MOTOR CORPORATION officially unveiled its newly developed next-generation lean-burn engine, which achieves combustion using the near-absolute minimal amount of fuel, resulting in greater fuel economy and lower emissions of CO2, a leading cause of global warming. This revised version of the engine came just 8 years after the first version was introduced in the Toyota Carina 1.6L and it also boasted better performance and response and a greater range of applications.

Toyota lean burn engine

In 1984, Toyota introduced the Toyota Lean Combustion System (T-LCS) in the Japanese market, becoming the world’s first automaker to employ such a system that controls the air-to-fuel ratio with a lean-mixture sensor. In 1987, the company launched a T-LCS high-performance, four-valve, twin-cam engine, which is still manufactured for Europe-bound compact vehicles. In Japan, lean-burn engines could meet strict emission standards only when fitted to smaller compact-class cars (23751b) with manual transmissions.

A product of innovative application and new technologies including the world’s first mass-produced combustion pressure sensor, the new 1.6-liter, four-valve, twin-cam engine realizes a major breakthrough as it achieves high performance and response with automatic and manual transmissions on larger compact-class (27501b) cars, while still clearing the strict Japanese emissions restrictions.

New technologies

  1. Combustion-pressure sensor

By directly monitoring combustion from the pressure inside the cylinder, the air-to-fuel ratio can be regulated with great control, achieving stable combustion at an air-to-fuel ratio very near the limit for lean-burn, greater fuel efficiency, and lower nitrogen oxide (NOx) emissions.

1984 Toyota lean burn engine

  1. Newly designed helical intake port

The new air-intake port ensures the optimum mixture swirl for lean burn, realizing lower intake resistance and superior fuel atomization and homogeneity in the mixture. This makes lean burn with lower NOx emissions possible in a wider range of driving conditions.

Toyota lean burn engine

  1. Electronically controlled EGR system

On automatic transmission models, the electronically controlled exhaust-gas recirculation (EGR) system is employed, enabling the lean-burn engine to recirculate more exhaust gas under driving conditions where engine load is great such as during acceleration by decreasing NOx emissions and improving fuel efficiency.

Toyota lean burn engine

Based on internal fuel-economy testing at the time carried out to Japanese standards, Toyota estimated that the new lean-burn engine achieved an 8 per cent increase in fuel economy for vehicles with manual transmission and 4 per cent for automatics, compared to vehicles with conventional engines. Overall, a 10 per cent improvement can be expected when combined with the driving system and other fuel-saving technologies.

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