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Chassis back and forth oscillation caused by sudden engine torque increase tends to occur, according to the characteristic of vehicle dynamics. This oscillation is called an acceleration surge and gives a vehicle driver a feeling of discomfort. This paper provides two control methods which can change the characteristic of vehicle acceleration response in order to suppress acceleration surge and to macth with driver's preference. The first control method is an acceleration servo method which is composed of control reference model and ignition timing control. The second control method is a variable response characteristic control algorithm. We treat the controlled object as the second order model with time delay, and assign the characteristic roots of transfer function in order to obtain the desired response.

A fuel injection control method is developed in which the transient air-fuel ratio is accurately controlled by an internal state estimation method with dynamic characteristics. With conventional methods the air-fuel ratio control precision is limited, because the air measurement system, the air and the fuel dynamic characteristics lack precision. In this development, the factors disturbing the air-fuel ratio under transient conditions are determined by analysis of the control mechanisms. The disturbance factors are found to be (1) the hot wire sensor has a delay time, (2) manifold air charging causes an overshoot phenomenon, (3) there is a dead time between sensing and fuel flow into the cylinder and (4) there is a delay of fuel flow into the cylinder caused by the fuel film. Compensation schemes are constructed for each of these technical problems.

This paper discusses causes and the mechanism of surging, back and forth chassis oscillation which occurs in cars with electronically controlled multi-point gasoline injection systems. This occurs during sharp acceleration, engine braking deceleration, and low speed coasting, at rather low ratio gear positions. We conclude that the mechanism of surging is parametric coupled oscillation. This conclusion is based on experimental data analysts and parameter sensitivity analysis using a chassis and engine dynamics simulator. The elements of parametric coupled oscillation are: a forcing system composed of engine control systems, engine and power transmission systems; a resonance system composed of axle and frame-body translation systems; a feedback system composed of axle translation systems and wheel revolution systems.