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A fuel reformer system that uses a steam reforming reaction in the exhaust gas recirculation (EGR) line with a catalyst was earlier proposed.(1) An analysis of engine test results revealed that not only hydrogen (H2) but also a H2 rich reformate additive in the air-fuel mixture was effective in suppressing knocking. To improve fuel economy via a high compression ratio, the knock limit is extended through the addition of H2 with its high octane number. In order to produce H2 on-board, we have proposed a fuel reformer for which the additions to the engine are an injector and a catalyst in the existing cooled EGR system. This method produces thicker H2 gas from gasoline by using heat and water vapor in the exhaust gas. The reformate mainly consists of H2, CO and CH4.

To improve the fuel economy via high EGR, combustion stability is enhanced through the addition of hydrogen, with its high flame-speed in air-fuel mixture. So, in order to realize on-board hydrogen production we developed a fuel reformer which produces hydrogen rich gas. One of the main issues of the reformer engine is the effects of reformate gas components on combustion performance. To clarify the effect of reformate gas contents on combustion stability, chemical kinetic simulations and single-cylinder engine test, in which hydrogen, CO, methane and simulated gas were added to intake air, were executed. And it is confirmed that hydrogen additive rate is dominant on high EGR combustion. The other issue to realize the fuel reformer was the catalyst deterioration. Catalyst reforming and exposure test were carried out to understand the influence of actual exhaust gas on the catalyst performance.

A new integrated control system has been developed for controlling an SI engine and a CVT proactively so as to obtain the demanded drive torque most efficiently. Taking into account ease of calibration, a control system configuration has been achieved that determines the CVT ratio from the target drive torque and vehicle speed, based on the steady-state relationship between the demanded drive torque and the vehicle speed, gear ratio, engine torque and fuel economy. An analysis was made of drive torque characteristics while the ratio was changing under transient conditions. The results showed that using engine torque to compensate for the ratio change response lag and inertia torque, which is proportional to the differential of the gear ratio, is effective in improving drive torque responsiveness.