The "X Bee" compact car, which Suzuki Motor Corp released Dec 25, 2017, comes with a mild hybrid system combining a 1.0L in-line three-cylinder direct-injection turbo gasoline engine and BSG ((belt starter generator).

The 1.0L direct-injection turbo engine, "K10C," was developed based on an engine used for Suzuki's "Swift" compact car. In the case of the Swift, its engine is not combined with a mild hybrid system. The X Bee is the first vehicle equipped with a mild hybrid system using a 1.0L direct-injection turbo engine.

The "X Bee" compact car

The Swift, which is a B-segment compact car, contains only the 1.0L direct-injection turbo engine in the engine compartment. On the other hand, the X Bee is an A-segment vehicle and needs to house the mild hybrid system combining the engine and BSG in a smaller engine compartment.

Therefore, the 1.0L direct-injection turbo engine of the X Bee is smaller than that of the Swift. Though it is equipped with a supercharger, its size is equivalent to that of a 1.2L naturally-aspirated engine.

To reduce the size, Suzuki thinned the inlet-exhaust pipe, compared with the Swift's engine. Also, the company changed the locations of a radiator, intercooler, etc. Through those improvements, it became possible to house the engine in the engine compartment.

The direct-injection turbo engine employed for the X Bee

However, the thinner inlet-exhaust pipe increases resistance when inlet and exhaust air passes through the pipe, causing a load on the engine. In view of this, Suzuki reduced the maximum output of the X Bee's 1.0L direct-injection turbo engine, compared with the Swift's engine. Also, the maximum rotation speed of the engine generating the highest torque is lower, compared with the Swift's engine.

On the other hand, when the X Bee's BSG is used as a driving motor, the maximum output and maximum torque are 2.3kW and 50N·m, respectively. The capacity of the lithium-ion (Li-ion) battery (for driving) located under the front passenger's seat is 120Wh. They are both the same as those of the "Ignis" compact car and "Wagon R" light car.

Original Japanese article