Development of an Electronic Resin Throttle Body 2011-01-2029

The need to improve fuel consumption by saving the weights of automobile parts is growing from the viewpoint of global warming mitigation. In the case of a throttle body for controlling the air flow volume into an engine, it is important to achieve a high dimensional accuracy of the valve-bore gap in the state of closed valve. In fact, most throttle bodies are made of precision-machined metal. Therefore, resin throttle bodies are drawing attention as a lightweight alternate. However, in comparison with metal throttle bodies, resin throttle bodies have two potential disadvantages that should be solved prior to productization. The first one is greater air leakage in the state of closed valve, and the second one is smaller heat conduction for unfreezing the valve in a frigid climate. We have developed an electronic resin throttle body that has overcome the above-mentioned disadvantages. The first disadvantage of greater leakage has been solved by the use of a world's first molding technology that allows simultaneous molding of the valve and bore with the same resin material in the same set of molding die under the same molding condition for improving the dimensional accuracy of valve-bore gap. In addition to that, the valve shape has been designed so as to increase the air-flow resistance at the valve-bore gap. The second disadvantage of smaller heat conduction has been compensated by the use of a double-bore structure for trapping the water droplets entrained in the air flow to the valve. This paper introduces the technological features of our electronic resin throttle body.