Search Results

On-Board Diagnostics II (OBD II), which will be to be introduced into motorcycles in Europe and India, requires that the engine oil and cooling water temperatures be monitored in a rational manner. The rationality of the sensors for engine oil and coolant temperatures (TW sensors) is derived from the ability to detect failure modes such as offset or fixation of unintended output voltage in addition to circuit continuity checks such as sensor harness disconnection and short circuit. The OBD II technology for 4-wheeled vehicles cannot be easily converted to motorcycles with their multiple cooling systems (air-cooled and water-cooled) and multiple heat dissipation structures (full fairings, naked structures, etc.). In previous studies, failures of the TW sensor were detected by estimating the water temperature with high accuracy based on the calorific value of the engine and the amount of heat dissipated.

We developed a novel method for reducing the engine noise associated with the high-pressure fuel system in gasoline direct-injection (DI) engines. We focused on the level of noise at idle running speed, because at the idle state, engine noise is the only noise source to the driver. The dominant vibration source of the high-pressure fuel system was fuel pulsation from the high-pressure fuel pump and activation noise of the solenoid-drive injector. To reduce the noise of the idling engine, we focused on the vibration transmission path from the high-pressure fuel system to the cylinder head, which results in noise radiation from the engine block. Next, we focused on the radiation noise associated with the pressurization event of the high-pressure fuel pump. To reduce the vibration transmission from the high-pressure fuel system to the cylinder head, the fuel rail and the injector were isolated from the cylinder head by avoiding metal-to-metal contact.

To meet the requirements for higher horsepower and torque as well as lower fuel consumption and emissions, we have developed a new “Intelligent Variable Valve Timing (VV-i)” system. It gives continuously variable intake cam phasing by up to 60 degrees crank angle (CA) . This system not only increases WOT output by optimizing intake valve closing timing but also reduces fuel consumption and NOx/ HC emissions under part load by increasing intake and exhaust valve overlap on 4 stroke Spark Ignited engines. VVT-i has been applied to optimize a new 3-liter inline 6 engine for higher torque and at the same time better fuel economy with continuous and wide-range cam phasing.

The usage of GPS (Global Positioning System) in various fields is growing. The best solution known for GPS outage problems in vehicle navigation systems is DR (dead reckoning). An inertial system based on distance and heading sensors backs up the GPS equipment by relaying information during periods without satellite visibility. Because the DR inertial system delivers relative positions and GPS absolute positions, it seems logical to combine the two to minimize the cumulative drift errors,mainly due to distance and heading sensor resolution. For in-vehicle GPS receiver, there are problems in maintaining the operation performance even in unfavorable environments like an urban area and using antenna layout which does not hinder the vehicle design. In the text,the solutions to these problems and a new type GPS receiving system which is equipped with Toyota Electro-Multivision(1) are described.