Daihatsu Introduces New, More Efficient Mini-Car Engine
26 November 2005
Daihatsu Motor has introduced its new KF minicar engine, previewed earlier this year at the Tokyo Motor Show. The 660cc Topaz KF achieves 5% greater torque, 10% better fuel economy and is 25% lighter than its predecessor.
The three-cylinder, 12-valve engine uses long-stroke pistons and ultra-compact combustion chambers, enhanced with high efficiency intake ports, friction-reduction technology, and high-strength aluminum cylinder block.
The engine generates peak output of 43 kW (58 hp) and peak torque of 65Nm.
Daihatsu will manufacture the KF engine together with the 1.0-liter 1KR minicar engine, which it developed in cooperation with Toyota Motor Corp. The firm plans to make the two engines at a combined rate of 1 million units a year.
The first car to carry the KF engine will be a new minicar model that Daihatsu plans to release in December. After that, it will use the new engine in a broader range of models.
To reduce emissions, Daihatsu is combining the KF engine with its “Super Intelligent Catalyst” technology, which is designed to prevent rhodium and other precious-metal catalyst materials from degrading and quickly activates the catalysts soon after the engine starts.
|Daihatsu“ Super Intelligent Catalyst”. Click to enlarge.|
The original “Intelligent Catalyst” provided self-regeneration in a palladium-based catalytic converter.
The technology achieved a major reduction in the amount of palladium used in automotive catalysts, and also lowered the cost of the catalyst. By the end of September 2005, the number of vehicles equipped with the original Intelligent Catalyst had exceeded 1,500,000 units.
The Super Intelligent Catalyst, also introduced at the Tokyo Motor Show in October, extends that self-regenerative function to support rhodium (Rh) and platinum (Pt), as well as the original palladium (Pd), thereby covering the three most commonly used precious metals in catalytic converters.
Automotive catalysts are continuously exposed to high operating temperatures of 800°C or more, causing the metal particles to agglomerate and grow, thereby decreasing overall surface area and deteriorating catalytic activity.
In anticipation of this degradation, an extra portion of precious metals is used in the manufacture of catalytic converters to compensate for the reduction of the working surface areas of the metals in order to maintain their catalytic performance for a longer time.
In the Super Intelligent Catalyst the metal ions of platinum and rhodium are placed in a special perovskite-type ceramic crystal lattice, and surrounded by six ions of oxygen.
Platinum and rhodium react in response to an inherent fluctuation in the oxygen concentration of exhaust gas from a gasoline engine. Platinum and rhodium come out of the perovskite-type ceramic crystal and form metallic nano-particles when there is insufficient oxygen.
Conversely, when there is surplus oxygen, the metallic nano-particles of platinum and rhodium return to the perovskite-type crystal as metal ions. This motion is repeated according to the natural fluctuation of the exhaust gas, and is called the self-regenerative function.
The motion of platinum and rhodium in and out of perovskite-type crystal occurs continuously, and the particle growth of platinum and rhodium is suppressed by the self-regenerative function. As a result, the Super Intelligent Catalyst is able to maintain excellent catalytic performance using only a small amount of precious metals.
The original Intelligent Catalyst with a self-regenerative function for palladium (Pd) was developed in 2002, and it contained lanthanum and iron as the LaFePdO3 perovskite. However, when the LaFeO3 perovskite crystal is used for platinum and rhodium, since the stable valences differ from Pd, the self-regeneration does not function well.
The new Super Intelligent Catalyst uses of a completely new perovskite-type crystal consisting of a different composition to support the additional metals.
The Super Intelligent Catalyst technology makes it possible to reduce the amount of precious metals used in catalysts, which should, in turn, reduce the cost.
“Self-regeneration of a Pd-perovskite catalyst for automotive emissions control”. Nishihata, Y. et al., Nature 418, 164-167 (2002).
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