Apparatus for detecting speed of vehicle with internal combustion engine

• US 4,748,565 A
• Filed: 07/23/1985
• Issued: 05/31/1988
• Est. Priority Date: 07/24/1984
• Status: Expired due to Term

• Current Assignee: Zezel Corporation
• Original Assignee: Diesel Japan Company Limited (Renzo Rosso)
• Inventors: Toya, Takaaki
• Primary Examiner(s): Lall, Parshotam S.
• Application Number:
  US06/758,048
• Time in Patent Office: 1,043 Days
• Field of Search: 364/431.07, 364/426, 364/424.1, 364/565, 364/424, 73/2, 73/506, 73/509, 73/510, 73/518, 324/160, 324/161, 324/163, 324/166
• US Class Current: 701/110
• CPC Class Codes: F16H 2059/706 Monitoring gear ratio in stepped transmissions, e.g. by calculating the ratio from input and output speed
• CPC Class Codes: F16H 59/70 dependent on the ratio established
• CPC Class Codes: G01P 3/56 for comparing two speeds

Abstract

In a speed detecting apparatus of a vehicle with an internal combustion engine whose rotational output is derived through a transmission, the apparatus comprises a circuit for calculating the gear ratio set in the transmission on the basis of the engine speed and a signal roughly indicative of the vehicle speed and a calculating circuit responsive to the result of the calculation in the circuit and the engine speed at each instant for calculating the speed of the vehicle at each instant. Thus, it is possible to accurately detect the vehicle speed at each instant in a short detection period.

Claims

1. An apparatus for calculating an instantaneous speed of a vehicle powered by an internal combustion engine whose rotational output is supplied through a transmission, which is set in a selectable gear ratio, to a wheel driving mechanism of said vehicle, said apparatus comprising:

a first means for producing a first signal indicating an instantaneous rotational speed of the internal combustion engine;

a second means for producing a second signal indicating an average running speed of the vehicle;

a third means for calculating a gear ratio set in the transmission in accordance with said first and second signals and for producing a third signal representing the calculated gear ratio; and

a fourth means for calculating the instantaneous vehicle speed in accordance with said first and third signals and producing output data indicative of the calculated instantaneous vehicle speed.

2. An apparatus as claimed in claim 1 wherein said first means has a first sensor for generating a first pulse every time an output shaft of the internal combustion engine rotates by a predetermined angle and means responsive to said first pulses for determining the speed of the internal combustion engine on the basis of the period of said first pulses and producing a signal indicating the determined engine speed as said first signal.

3. An apparatus as claimed in claim 1 wherein said second means includes a second sensor which operates in response to the rotation of a speedometer cable provided on the output side of the transmission and produces a second pulse every time the speedometer cable rotates by a predetermined angle.

4. An apparatus as claimed in claim 3 wherein said second means has means responsive to said second pulses for determining the speed of the vehicle on the basis of the period of said second pulses and producing vehicle speed data indicating the determined vehicle speed, and means responsive to said vehicle speed data for calculating the average vehicle speed on the basis of a plurality of vehicle speed data received thereby and producing a signal indicating the calculated average vehicle speed as said second signal.

5. An apparatus as claimed in claim 1 wherein said third means has a computing means responsive to said first and second signals for producing a gear ratio signal, a filtering means for effecting a filtering operation on said gear ratio signal with first order lag characteristic, means responsive to the gear ratio signal for detecting whether or not the change in the gear ratio is more than a predetermined value, and means responsive to the output of said detecting means for selecting either said gear ratio signal or the output from said filtering means as said third signal.

6. An apparatus as claim in claim 5 wherein said computing means has means responsive to said first signal which calculates the average engine speed of the internal combustion engine and produces an average engine speed signal indicating the calculated average engine speed, and means responsive to said average engine speed signal and said second signal for calculating the ratio between the average engine speed and the average vehicle speed and producing said gear ratio signal in accordance with said gear ratio.

7. An apparatus as claimed in claim 5 wherein said selecting means operates in such a way that said gear ratio signal is selected when the change in the gear ratio is more than the predetermined value and the output from said filtering means is selected when the change in the gear ratio is not more than the predetermined value.

8. An apparatus as claimed in claim 7 wherein said selecting means selects said gear ratio signal only when the change in the speed change ratio continues to be more than the predetermined value for a predetermined period.